KR20250036234A - Golf club head with optimized moment of inertia - Google Patents

Abstract

A driver type golf club head according to the present invention comprises a cubic body shape having a body height to body depth ratio of 0.5 to 0.75 and a body height to body width ratio of 0.5 to 0.75. The golf club head further comprises a mass distribution in which a significant portion of the mass of the club head is located within a center mass region centered about the Y'-axis. The golf club head further comprises an Ixx moment of inertia and an Iyy moment of inertia, wherein the Ixx/Iyy ratio is greater than 0.8. In many embodiments, the golf club head further comprises optimized bulge and roll curvatures determined by the Ixx, Iyy, CG location, coefficient of restitution, and/or other characteristics.

Description

Golf club head with optimized moment of inertia

Cross-reference priority

This application claims the benefit of U.S. Provisional Application No. 63/503,134, filed May 18, 2023, U.S. Provisional Application No. 63/370,482, filed August 4, 2022, and U.S. Provisional Application No. 63/368,626, filed July 15, 2022, all of which are incorporated herein by reference in their entirety.

The present disclosure relates generally to golf equipment, and particularly to golf heads. In particular, the present invention relates to golf club heads having optimized moments of inertia and/or optimized bulge and roll curvatures.

Historically, golf club head design, particularly wood-type golf club head design, has tended to increase the moment of inertia of the clubhead to provide more forgiveness and minimize the loss of velocity due to mis-hits. Most conventional clubhead designs focus on increasing the Iyy moment of inertia (i.e., the moment of inertia about the Y-axis, which runs vertically through the clubhead's center of gravity) because Iyy has a major impact on the performance and forgiveness of the clubhead, particularly on mis-hit shots toward the heel or toe. These clubheads are designed to achieve the highest possible Iyy. Conventional clubhead designs that attempt to maximize Iyy often include a flat body profile with a large perimeter of weight that places most of the discretionary mass away from the Y-axis. However, in maximizing Iyy, conventional clubhead designs often ignore other characteristics such as the Ixx moment of inertia (i.e., the moment of inertia about the X-axis through the clubhead’s center of gravity) and bulge and roll curvature. Excessively low Ixx and/or bulge and roll curvature that is not optimized for a particular clubhead can result in reduced forgiveness and distance on mis-hits, even with a high Iyy.

In certain instances, it may be desirable to provide a wood type club head that achieves a specific Iyy target value. In many instances, a lower Iyy target value than that of a typical conventional club head may be desired. In some instances, it may be desirable to set a lower Iyy target value to fit the club head to a specific player or a subset of players. However, since Iyy has a significant effect on the forgiveness and performance of a club head, designing a club head with a low Iyy target value may have a negative effect on the forgiveness and performance of the club head. There is a need to maximize the performance of a club head with respect to achieving a target Iyy. In particular, there is a need in the art to maximize the performance of a club head that achieves a target Iyy that is lower than that of a typical conventional club head by maintaining a balance of Ixx, Iyy, CG location, and bulge and roll curvature.

FIG. 1 is a front perspective view of a golf club head according to the present invention.
Figure 2 is a front view of the golf club head of Figure 1, with the club head coordinate axis highlighted.
Figure 3 is a toe-side drawing of the golf club head of Figure 1, with the club head coordinate axis highlighted.
Figure 4 is a plan view of the golf club head of Figure 1, highlighting the club head body dimensions.
Figure 5 is a front view of the golf club head of Figure 1, highlighting the striking surface dimensions.
Figure 6 is a toe-side drawing of the golf club head of Figure 1, highlighting the striking surface dimensions and crown angle.
Figure 7 illustrates a front perspective view of the golf club head of Figure 1 within a virtual reference cube.
Figure 8 is a plan view of the golf club head of Figure 1, highlighting the imaginary central mass area.
Figure 9 is a toe-side drawing of the golf club head of Figure 1, highlighting the imaginary central mass area.
Figure 10 illustrates a toe-side cross-sectional view of the golf club head of Figure 1.
FIG. 11 illustrates a rear perspective view of a club head according to the present invention including an adjustable weight member.
FIG. 12 illustrates a plan view of a golf club head according to the present invention further including non-metallic components.
FIG. 13 illustrates a plan view of a second embodiment of a golf club head according to the present invention further comprising a non-metallic component.
Figure 14 illustrates a bottom view of the golf club head of Figure 13.
FIG. 15 illustrates a toe-side cross-sectional view of a golf club head including an adjustable swing weight system according to a first embodiment.
FIG. 16 illustrates a plurality of weight inserts configured to be accommodated within the club head of FIG. 15.
FIGS. 17a-17c illustrate toe-side cross-sectional views of the club head of FIG. 15 for a multiple weight insert configuration.
FIG. 18 illustrates a toe-side cross-sectional view of a golf club head of a first configuration including an adjustable swing weight system according to a second embodiment.
Figure 19 illustrates a toe-side cross-sectional view of the golf club head of Figure 18 of the second configuration.
FIG. 20 illustrates a toe-side cross-sectional view of the golf club head of FIG. 18 of the third configuration.
FIG. 21 illustrates a toe-side cross-sectional view of a golf club head including an adjustable swing weight system according to a third embodiment.
FIG. 22 illustrates a toe-side cross-sectional view of a golf club head including an adjustable swing weight system according to a fourth embodiment.
FIG. 23 illustrates a top cross-sectional view of a golf club head according to the present invention including a plurality of internal ribs.
FIG. 24 illustrates a detailed cross-sectional view of a golf club head including a lightweight adjustable shaft receiving structure.
Figure 25 illustrates a graphical diagram showing the relationship between the bulge radius and the offline distance according to the first embodiment.
Figure 26 illustrates a graphical diagram showing the relationship between the bulge radius and the offline distance according to the second embodiment.
Other aspects of the present invention will become apparent from consideration of the detailed description and the accompanying drawings.
For simplicity and clarity of explanation, the drawings represent general construction schemes, and descriptions and details of well-known features and techniques may be omitted so as not to unnecessarily obscure the present disclosure. In addition, elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help understand embodiments of the present disclosure. Like reference numerals in different drawings indicate like elements.

Definition

In this specification and claims, the terms “first,” “second,” “third,” “fourth,” etc., are used to distinguish similar elements where present and are not necessarily intended to describe a particular sequential or chronological order. The terms so used are to be understood to be interchangeable, so that the embodiments described herein can be operated in sequences other than those illustrated or otherwise described herein, for example. Furthermore, the words “comprise,” “have,” and variations thereof are intended to encompass a non-exclusive inclusion, such that a process, method, system, article, apparatus, or device that includes a list of elements is not necessarily limited to just those elements, but may include other elements not expressly listed or inherent in the process, method, system, article, apparatus, or device.

In the description and claims, where present, the terms “left,” “right,” “front,” “rear,” “upper,” “bottom,” “above,” “below,” and the like are used for descriptive purposes and are not necessarily intended to describe permanent relative positions. It is to be understood that the terms so used are interchangeable in appropriate contexts so that the embodiments of the invention described herein can be operated in orientations other than those illustrated or otherwise described herein.

The terms "couple", "coupled", and "coupling" should be understood broadly and refer to connecting two or more elements or signals electrically, mechanically, and/or in any other manner.

Various embodiments of a golf club are illustrated in the drawings. A golf club is generally understood to include a club head configured to receive a shaft. The golf club further includes a grip secured to the shaft.

FIGS. 1-6 are schematic drawings illustrating various embodiments of a driver type golf club head from various perspectives. The features described below are demonstrated on the club head (100). For convenience of discussion, the features shown on the club head (100) may be applied to various embodiments of the club head according to the present invention. Any one or more of the features described in the various embodiments below may be used in combination with each other. Additionally, although different embodiments may include different numbering schemes (i.e., 1xx, 2xx, 3xx numbering schemes, etc.), similar elements are numbered similarly between the embodiments (i.e., the club head (100) includes a crown (110) and a sole (112), and the club head (200) includes a crown (210) and a sole (212)).

A club head (100) may include a striking face (102) and a body (101) secured together to form a substantially closed/hollow internal cavity. The club head (100) includes a crown (110), a sole (112) opposite the crown (110), a heel (104), a toe (106) opposite the heel (104), a forward end (108), and a rear end (111) opposite the forward end (108). The body (110) may further include a skirt (114) and/or a trailing edge (109) positioned adjacent to and between the crown (110) and the sole (112). The skirt (114) may extend from near the heel (104) of the club head (100) to near the toe (106).

The club head (100) may include one or more body materials, such as steel, stainless steel, tungsten, aluminum, titanium, vanadium, chromium, cobalt, nickel, or other metals or metal alloys. In some embodiments, the body material may include Ti-8Al-1Mo-1V alloy or 17-4 stainless steel. In some embodiments, the body material may be formed of a C300, C350, a Ni-Co-Cr-Steel alloy, a 565 steel, an AISI Type 304 or AISI Type 630 stainless steel, a 17-4 stainless steel, a titanium alloy - such as, but not limited to, Ti-6-4, Ti-3-8-6-4-4, Ti-10-2-3, Ti 15-3-3-3, Ti 15-5-3, Ti185, Ti 6-6-2, Ti-7s, Ti-9s, Ti-92 or Ti-8-1-1 titanium alloys - an amorphous metal alloy, or other similar metal. In some embodiments, one or more portions of the club head (100) may comprise a non-metallic material.

As used herein, the term "ground plane" refers to a reference plane relative to the surface on which the golf ball rests. The ground plane (1010) may be a horizontal plane that contacts the sole at the address position. The address position is defined in more detail below. The ground plane (1010) is illustrated in FIG. 2.

The term "loft plane" as used herein refers to a reference plane that is tangent to the geometric center of the striking surface (the "geometric center" is described in more detail below). The loft plane (1015) is illustrated in FIG. 3.

The term "loft angle" as used herein may refer to the angle measured between the loft plane (1015) and the XY plane (defined below). The loft angle (10) is illustrated in FIG. 3.

The term "lie angle" as used herein may refer to the angle between the hosel axis (1020) extending through the hosel (105) and the ground plane. The lie angle (15) is measured from the front of the club head as illustrated in FIG. 2.

The club head (100) can define an "address position" (also referred to as an "address") in which the club head is oriented to form an intended loft angle (10) and lie angle (15). For example, at the address position, the loft plane (1015) and the XY plane form an intended loft angle (10) with respect to each other. Similarly, at the address position, the hosel axis (1020) and the ground plane (1010) form an intended lie angle (15) with respect to each other.

As illustrated in FIGS. 2 and 3, the club head (100) can define a basic coordinate system centered around the geometric center (120) of the striking surface (102). The basic coordinate system can include an X-axis (1040), a Y-axis (1050), and a Z-axis (1060). The X-axis (1040) can extend in a heel-toe direction parallel to the ground plane (1010). The X-axis (1040) can be positive toward the heel (104) and negative toward the toe (106). The Y-axis (1050) can extend in a crown-sole direction and can be orthogonal to both the ground plane 1010 and the X-axis (1040). The Y-axis (1050) can be positive toward the crown (110) and negative toward the sole (112). The Z-axis (1060) can extend in the forward and backward direction parallel to the ground plane (1010) and can be orthogonal to both the X-axis (1040) and the Y-axis (1050). The Z-axis (1060) can be positive toward the striking surface (102) and negative toward the rear end (108).

As described herein, the base coordinate system defines the XY plane as a vertical plane extending along the X-axis (1040) and the Y-axis (1050). The base coordinate system defines the XZ plane as a horizontal plane extending along the X-axis (1040) and the Z-axis (1060). Additionally, the base coordinate system defines the YZ plane as a vertical plane extending along the Y-axis (1050) and the Z-axis (1060). The XY plane, the XZ plane, and the YZ plane are all perpendicular to one another and intersect at the base coordinate system origin located at the geometric center (120) of the striking face (102). In these or other embodiments, the club head (100) is viewed from the front when looking at the striking face (102) in a direction perpendicular to the XY plane. Additionally, in these or other embodiments, the club head (100) may be viewed in a side view or cross-sectional side view when looking at the heel (104) or toe (106) in a direction perpendicular to the YZ plane.

The “body depth” or “depth” (D _B ) of the club head (100) as used herein refers to the fore-aft dimension measured across the body (101). Referring to FIGS. 3 and 4 , the body depth (D _B ) is measured parallel to the Z-axis (1060) from the leading edge (103) of the body (101) to the rearmost point (117).

The "body height" or "height" (H _B ) of the club head (100) described herein may refer to the crown-to-sole dimension measured across the body (101). Referring to FIG. 2 , the body height (H _B ) may be measured as the vertical distance (parallel to the Y-axis (1050)) between the ground plane (1010) and the highest point of the crown (110). In many embodiments, the body height (H _B ) may be measured according to a golf governing body, such as the United States Golf Association (USGA).

The "body width" or "width" (W _B ) of the club head (100) described herein may refer to a heel-to-toe dimension measured across the body (101). Referring to FIG. 2 , the body width (W _B ) may be measured parallel to the X-axis (1040) from the heel vertex (116) to the toe vertex (119). The toe vertex (119) is defined as the toe-side maximum point of the body (101). The heel vertex (116) is the heel-side maximum point of the heel (104) located 0.875 mm above the ground plane (1010). In many embodiments, the body width (W _B ) may be measured according to a golf governing body, such as the United States Golf Association (USGA). The ranges specified for body depth (D _B ), body height (H _B ), and body width (W _B ) may be designed according to the USGA rules.

The "center of gravity" or "CG" of a club head as described herein may refer to the point at which mass is centered within the club head. The CG (160) is described in FIGS. 2 and 3.

The term or phrase "center of gravity location" or "CG location" may refer to the location of a club head center of gravity (CG) with respect to a base coordinate system, wherein the CG location is characterized as being located along the X-axis (1040), the Y-axis (1050), and the Z-axis (1060). The term "CGx" may refer to the CG location along the X-axis (1040) measured from the geometric center (120). The term "CG height" may refer to the CG location along the Y-axis (1050) measured from the geometric center (120). The term "CGy" may be synonymous with CG height. The term "CG depth" may refer to the CG location along the Z-axis (1060) measured from the geometric center (120). The term "CGz" may be synonymous with CG depth.

The golf club head additionally includes an auxiliary coordinate system centered about a center of gravity (160). As illustrated in FIGS. 2 and 3, the auxiliary coordinate system includes an X'-axis (1070), a Y'-axis (1080), and a Z'-axis (1090). The X'-axis (1070) extends in a heel-toe direction. The X'-axis (1070) is positive toward the heel (104) and negative toward the toe (106). The Y'-axis (1080) extends in a sole-crown direction and is orthogonal to both the Z'-axis (1090) and the X'-axis (1070). The Y'-axis (1080) is positive toward the crown (110) and negative toward the sole (112). The Z'-axis (1090) extends forward and backward parallel to the ground plane (1010) and is orthogonal to both the X'-axis (1070) and the Y'-axis (1080). The Z'-axis (1090) is positive toward the striking surface (102) and negative toward the rear end (111).

The term or phrase "moment of inertia" (hereinafter "MOI") may refer to a value derived using a center of gravity (CG) location. The term "MOIxx" or "Ixx" may refer to the MOI measured about the X'-axis (1070). The term "MOIyy" or "Iyy" may refer to the MOI measured about the Y'-axis (1080). The term "MOIzz" or "Izz" may refer to the MOI measured about the Z'-axis (1090). The MOI values (MOIxx, MOIyy and MOIzz) determine how forgiving the club head (100) is to eccentric impacts with a golf ball.

MOI is a measure of an object's torsional resistance about a given axis and is calculated according to Equation 1 below.

(Formula 1)

Equation 1 is the MOI (denoted by I) of an object as an integral of its mass (denoted by dm), which is defined as the square of the perpendicular distance (denoted by r) between the axis along which the MOI is measured and the location of the object's mass. In general, if the center of gravity (CG) of an object is known, the object can be treated as a point mass located at that CG. Treating an object as a point mass simplifies Equation 1 to Equation 2 below.

(Formula 2)

Equation 2 states that the moment of inertia (I) of an object about a given axis is equal to the sum of the masses of all point masses of that object multiplied by the perpendicular distance between each point mass and the axis along which the MOI is measured.

The term "strike face" as used herein refers to the front surface of the club head configured to strike a golf ball. The term strike face may be used interchangeably with the term "face".

The term "strikeface perimeter" as used herein may refer to an edge of the strikeface. The strikeface perimeter may be located along the outer edge of the strikeface where the curvature of the club head deviates from the bulge and/or roll curvature (defined below) of the strikeface. Referring to FIG. 5, the strikeface perimeter includes a top edge (118) defining a highest point of the strikeface (102). The strikeface perimeter further includes a leading edge (103) defining a lowest point of the strikeface (102). The strikeface perimeter is the outermost boundary of the strikeface (102).

The "leading edge" of the club head as described herein may be identified as the sole-side maximum portion of the striking face perimeter. For example, as illustrated in FIG. 5, the leading edge (103) is the portion of the club head (100) that transitions from the striking face (102) to the sole (112).

The "striking face height" (H _SF ) of the club head as used herein refers to the distance measured from the lowest point on the perimeter of the striking face to the highest point on the perimeter of the striking face. Referring to FIGS. 5 and 6 , the height (H _SF ) can be measured parallel to the loft plane (1015) from the leading edge (103) of the striking face (102) to the top edge (118), where the top edge (118) represents the crown-side maximum portion of the perimeter of the striking face (102).

The "strikeface width" (W _SF ) of a club head as used herein refers to the horizontal distance measured across the strikeface in the heel-toe direction. Referring to FIG. 5 , the strikeface width (W _SF ) may be measured parallel to the ground plane (1010) from the heel-side maximum extension to the toe-side maximum extension around the strikeface.

The "geometric center" of the striking face as used herein refers to the geometric center point of the striking face perimeter as described in FIGS. 2 and 5. The geometric center point (120) of the striking face (102) may be located according to the definition of a golf governing body, such as the United States Golf Association (USGA).

As illustrated in FIG. 6, the striking surface (102) has a geometric center height (H _FC ). The geometric center height (H _FC ) is measured from the leading edge (103) parallel to the loft plane (1015) to the geometric center (120).

The striking surface has a "bulge curvature" and a "roll curvature". The bulge curvature is the curvature of the striking surface in the heel-toe direction. The roll curvature is the curvature of the striking surface in the crown-sole direction. The bulge curvature and the roll curvature each have a "bulge radius" and a "roll radius", which define the radii of curvature associated with the bulge curvature and the roll curvature, respectively. The bulge curvature and/or the roll curvature may have more than one radius.

As illustrated in FIG. 6, the club head (100) further includes a force line (125) that intersects the geometric center (120) and extends parallel to the loft plane (1015). The launch characteristics of a golf ball depend on the relationship between the force line (125) and the CG (160). The closer the CG (160) is to the force line (125), the greater the energy transfer between the club head (100) and the golf ball at impact. The launch characteristics of the club head (100) at impact remain substantially consistent even if the CG (160) moves relative to the remainder of the club head (100) as long as the distance between the CG (160) and the force line (125) is constant.

Before explaining any embodiments of the present disclosure in detail, it is to be understood that the present disclosure is not limited in its application to the details of construction and arrangement of the components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

details

The golf club heads described herein include various features and characteristics to maximize performance given a specific moment of inertia target value. In particular, the club heads described herein can be designed to achieve a specific Iyy target value and maximize performance and forgiveness for the limits of that Iyy target value. In general, the higher the Iyy, the more forgiving the club head. A club head with a higher Iyy has greater rolling resistance at impact on a heel-side or toe-side shot from the center. A club head with a higher Iyy retains more energy at impact on a heel-side or toe-side mis-hit. Accordingly, a club head with a higher Iyy generally provides greater restraint and distance on a heel-side or toe-side mis-hit. However, there are other factors that affect club head forgiveness and overall performance, such as the Ixx moment of inertia and the bulge and roll curvature. The embodiments described herein provide features and characteristics that increase the Ixx relative to the Iyy target value. Embodiments described herein further include optimized bulge and roll curvatures determined by the Iyy target values combined with other club head characteristics (i.e., Ixx, CG location, coefficient of restitution, etc.). Increasing the Ixx can provide increased forgiveness and distance on crown-side or sole-side mis-hits. Optimizing the bulge and roll curvature can further increase distance forgiveness by counteracting the gear effect on the golf ball on off-center hits. In particular, embodiments described herein relate to a driver type golf club head (designed primarily for striking a golf ball off a tee) that includes a particular Iyy target value. The embodiments are not limited to fairway wood type, hybrid type, or iron type club heads. While the driver type club head described herein is intended for striking a golf ball off a tee, the club head may also be suitable for striking a golf ball off the ground.

As discussed above, there are two key characteristics of the club head that provide improved performance for a fixed Iyy target: 1) the Ixx moment of inertia and 2) the bulge and roll curvature. The club head of the present disclosure provides a high Ixx moment of inertia relative to the Iyy target. In many embodiments, the club head can have an Ixx/Iyy ratio greater than 0.80. Providing a high Ixx relative to the Iyy target increases the overall forgiveness of the club head. Ixx represents the resistance to rotation of the club head about the X'-axis on a golf shot struck above or below center. As described in the definitions above, the X'-axis is the heel-toe axis in a coordinate system centered at the club head CG. The X'-axis extends horizontally through the CG in the heel-toe direction. In particular, a high Ixx/Iyy ratio provides increased resistance to rotation about the X'-axis at impact on shots that are centered toward the crown or sole with respect to the clubhead. An increased Ixx/Iyy ratio increases golf shot distance on crown-side or sole-side mis-hits by reducing the effect of the clubhead's rotation about the X'-axis and balancing the backspin of the golf ball.

The club head maximizes the Ixx/Iyy ratio by distributing most of the club head mass near the Y'-axis through a "cubic" shaping. The club head has a cubic profile in which the body width, body height, and body depth are similar to those of prior art club heads. The cubic profile of the club head increases Ixx without affecting Iyy by distributing the mass of the crown and sole away from the X'-axis. Most prior art club heads, especially modern club heads, have a flat, wide, deep profile in which the body height is much smaller than the body width or body depth. These prior art club heads prefer to increase Iyy regardless of Ixx. These prior art club head shapes effectively increase Iyy by distributing the club head mass away from the Y'-axis through their shaping. However, these designs do not prioritize the amount of structural mass that is distributed away from the X'-axis and therefore do not maximize the Ixx/Iyy ratio.

To maximize the Ixx/Iyy ratio, the club head efficiently distributes mass so that it contributes to Ixx rather than Iyy. The club head can distribute a significant portion of its mass near the Y'-axis but away from the X'-axis. To achieve this mass distribution, the club head can include one or more weighting features, such as internal mass pads or removable weights, positioned near the Y'-axis and away from the X-axis. Any of these features can serve to significantly increase Ixx relative to Iyy, thereby increasing the Ixx/Iyy ratio.

A club head can include a striking face having optimized bulge and roll curvatures to increase performance and forgiveness. The bulge and roll curvatures can be specifically tailored to a particular club head based on characteristics of that club head including Ixx, Iyy, CG location, coefficient of restitution, and/or other club head characteristics. The club head can maximize distance and forgiveness by satisfying one or more bulge radius or roll radius relationships. The bulge and roll radii of the club head counteract the gear effect on the golf ball when struck off-center. Providing bulge and roll radii based on the characteristics of the club head can increase forgiveness and distance, thereby providing a higher performing club head even when the Iyy target is significantly lower. In embodiments where the Iyy target is significantly lower, the optimized bulge and roll radii can compensate for the loss of forgiveness and rigidity associated with a low Iyy target.

In some embodiments, the club head may further include an adjustable swing weight system that provides multiple club head geometries usable at consistent Iyy targets. The adjustable swing weight system includes a plurality of replaceable and/or removable weight inserts, each configured to provide a consistent Iyy contribution. The adjustable swing weight system provides the ability to maintain Iyy consistent across different geometries while varying the total club head mass by greater than 25 g.

I. Iyy target value and mass characteristics

As described above, the club heads of the present invention are designed to achieve a specified Iyy moment of inertia target value (hereinafter, "Iyy target value"). In some embodiments, the Iyy target value may substantially match the moment of inertia limit imposed by the USGA for a conforming club head. However, in many embodiments, the Iyy target value may be lower than the USGA limit. A club head designed to achieve an Iyy target value at or near the USGA limit may be referred to herein as a "high-MOI" club head, while a club head designed to achieve an Iyy target value that is well below the USGA limit may be referred to herein as a "low-MOI" club head. While the embodiments and examples herein primarily relate to low-MOI club heads, any combination of the principles, features, characteristics, elements or methods disclosed below may also be applied to high-MOI club heads. Unless otherwise specified, the mass characteristics described herein, including moment of inertia values and CG locations, reflect a "fully structured" club head. A fully structured club head includes all applicable weight inserts, removable weights, permanent weights, swing weights, filler and/or any other removable components associated with the adjustable hosel assembly.

In a high-MOI club head embodiment, the Iyy target may be between 4000 g*cm2 and 8000 g*cm2. In some high-MOI club head embodiments, the Iyy target value is in the range of 4000 g*㎠ to 4200 g*㎠, 4200 g*㎠ to 4400 g*㎠, 4400 g*㎠ to 4600 g*㎠, 4600 g*㎠ to 4800 g*㎠, 4800 g*㎠ to 5000 g*㎠, 5000 g*㎠ to 5200 g*㎠, 5200 g*㎠ to 5400 g*㎠, 5400 g*㎠ to 5600 g*㎠, 5600 g*㎠ to 5800 g*㎠, 5800 g*㎠ to 6000 g*㎠, 6000 It can be from g*㎠ to 6500 g*㎠, from 6500 g*㎠ to 7000 g*㎠, from 7000 g*㎠ to 7500 g*㎠, or from 7500 g*㎠ to 8000 g*㎠. In some high-MOI club head embodiments, the Iyy target value can be greater than 4000 g*cm2, greater than 4200 g*cm2, greater than 4400 g*cm2, greater than 4600 g*cm2, greater than 4800 g*cm2, greater than 5000 g*cm2, greater than 5200 g*cm2, greater than 5400 g*cm2, greater than 5600 g*cm2, or greater than 5800 g*cm2, greater than 6000 g*cm2, greater than 6500 g*cm2, greater than 7000 g*cm2, greater than 7500 g*cm2, or greater than 8000 g*cm2. Embodiments of the high-MOI club head can have an Iyy moment of inertia within any of the Iyy target ranges listed above.

In a low-MOI club head embodiment, the Iyy target may be between 2000 g*cm2 and 4000 g*cm2. In some low-MOI club head embodiments, the Iyy target can be from 2000 g*cm2 to 2200 g*cm2, from 2200 g*cm2 to 2400 g*cm2, from 2400 g*cm2 to 2600 g*cm2, from 2600 g*cm2 to 2800 g*cm2, from 2800 g*cm2 to 3000 g*cm2, from 3000 g*cm2 to 3200 g*cm2, from 3200 g*cm2 to 3400 g*cm2, from 3400 g*cm2 to 3600 g*cm2, from 3600 g*cm2 to 3800 g*cm2, or from 3800 g*cm2 to 4000 g*cm2. In some low-MOI club head embodiments, the Iyy target value can be less than 4000 g*cm2, less than 3800 g*cm2, less than 3600 g*cm2, less than 3400 g*cm2, less than 3200 g*cm2, less than 3000 g*cm2, less than 2800 g*cm2, less than 2600 g*cm2, less than 2400 g*cm2, or less than 2200 g*cm2, or less than 2000 g*cm2. Embodiments of the low-MOI club head can have an Iyy moment of inertia within any of the Iyy target ranges listed above.

As described above, the club head described herein achieves a high Ixx/Iyy ratio (greater than 0.80) by distributing most of the club head mass near the Y'-axis via the cubic shaping. Accordingly, the club head can have an Ixx value substantially close to the Iyy target value. In high-MOI club head embodiments, the club head can have an Ixx of from 3200 g*cm2 to 7200 g*cm2. In some high-MOI club head embodiments, Ixx can be from 3200 g*㎠ to 3600 g*㎠, from 3600 g*㎠ to 4000 g*㎠, from 4000 g*㎠ to 4400 g*㎠, from 4400 g*㎠ to 4800 g*㎠, from 4800 g*㎠ to 5200 g*㎠, from 5200 g*㎠ to 5600 g*㎠, from 5600 g*㎠ to 6000 g*㎠, from 6000 g*㎠ to 6400 g*㎠, from 6400 g*㎠ to 6800 g*㎠, or from 6800 g*㎠ to 7200 g*㎠. In some high-MOI club head embodiments, Ixx can be greater than 3200 g*cm2, greater than 3600 g*cm2, greater than 4000 g*cm2, greater than 4400 g*cm2, greater than 4800 g*cm2, greater than 5200 g*cm2, greater than 5600 g*cm2, greater than 6000 g*cm2, greater than 6400 g*cm2, greater than 6800 g*cm2, or greater than 7200 g*cm2.

In a low-MOI club head embodiment, the club head can have an Ixx of from 1400 g*cm2 to 3600 g*cm2. In some low-MOI club head embodiments, Ixx is from 1400 g*㎠ to 1600 g*㎠, from 1600 g*㎠ to 1800 g*㎠, from 1800 g*㎠ to 2000 g*㎠, from 2000 g*㎠ to 2200 g*㎠, from 2200 g*㎠ to 2400 g*㎠, from 2400 g*㎠ to 2600 g*㎠, from 2600 g*㎠ to 2800 g*㎠, from 2800 g*㎠ to 3000 g*㎠, from 3000 g*㎠ to 3200 g*㎠, from 3200 g*㎠ to 3400 g*㎠, or from 3400 g*㎠ or greater than 3600 g*cm2. In some low-MOI club head embodiments, Ixx may be greater than 1400 g*cm2, greater than 1600 g*cm2, greater than 1800 g*cm2, greater than 2000 g*cm2, greater than 2200 g*cm2, greater than 2400 g*cm2, greater than 2600 g*cm2, greater than 2800 g*cm2, greater than 3000 g*cm2, greater than 3200 g*cm2, greater than 3400 g*cm2, or greater than 3600 g*cm2.

The CG (160) location of the club head (100) can vary depending on the Iyy target, club head volume, and other factors. In high-MOI embodiments, the club head (100) can have a CGy location between 0 inches and -0.5 inches, measured from the geometric center (120) of the striking face (102). In some high-MOI embodiments, the CGy location can be between 0 inches and -0.05 inches, between -0.05 inches and -0.10 inches, between -0.10 inches and -0.15 inches, between -0.15 inches and -0.20 inches, between -0.20 inches and -0.25 inches, between -0.25 inches and -0.30 inches, between -0.35 inches and -0.40 inches, between -0.40 inches and -0.45 inches, or between -0.45 inches and -0.50 inches. In some high-MOI embodiments, the CGy location can be less than 0 inches, less than -0.05 inches, less than -0.10 inches, less than -0.15 inches, less than -0.20 inches, less than -0.25 inches, less than -0.30 inches, less than -0.35 inches, less than -0.40 inches, less than -0.45 inches, or less than -0.50 inches.

In a high-MOI embodiment, the club head (100) can have a CGz location of -1.25 inches to -2.0 inches measured from the geometric center (120) of the striking face (102). In some high-MOI embodiments, the CGz location can be -1.25 inches to -1.30 inches, -1.30 inches to -1.35 inches, -1.35 inches to -1.40 inches, -1.40 inches to -1.45 inches, -1.45 inches to -1.50 inches, -1.50 inches to -1.55 inches, -1.55 inches to -1.60 inches, -1.60 inches to -1.65 inches, -1.65 inches to -1.70 inches, -1.70 inches to -1.75 inches, -1.75 inches to -1.80 inches, -1.80 inches to -1.85 inches, -1.85 inches to -1.90 inches, -1.90 inches to -1.95 inches, or -1.95 inches to -2.0 inches. In some high-MOI embodiments, the CGz location can be less than -1.25 inches, less than -1.30 inches, less than -1.35 inches, less than -1.40 inches, less than -1.45 inches, less than -1.50 inches, less than -1.55 inches, less than -1.60 inches, less than -1.65 inches, less than -1.70 inches, less than -1.75 inches, less than -1.80 inches, less than -1.85 inches, less than -1.90 inches, less than -1.95 inches, or less than -2.0 inches.

In low-MOI embodiments, the club head (100) can have a CGy location of from -0.30 inches to 0.30 inches, measured from the geometric center (120) of the striking face (102). In some low-MOI embodiments, the CGy location can be from -0.30 inches to -0.25 inches, from -0.25 inches to -0.20 inches, from -0.20 inches to -0.15 inches, from -0.15 inches to -0.10 inches, from -0.10 inches to -0.05 inches, from -0.05 inches to 0 inches, from 0 inches to 0.05 inches, from 0.05 inches to 0.10 inches, from 0.10 inches to 0.15 inches, from 0.15 inches to 0.20 inches, from 0.20 inches to 0.25 inches, or from 0.25 inches to 0.30 inches. In some low-MOI embodiments, the CGy location can be less than 0.30 inches, less than 0.25 inches, less than 0.20 inches, less than 0.15 inches, less than 0.10 inches, less than 0.05 inches, less than 0 inches, less than -0.05 inches, less than -0.10 inches, less than -0.15 inches, less than -0.20 inches, less than -0.25 inches, or less than -0.30 inches.

In a low-MOI embodiment, the club head (100) can have a CGz location of -1.0 inches to -1.75 inches measured from the geometric center (120) of the striking face (102). In some low-MOI embodiments, the CGz location can be -1.0 inch to -1.05 inch, -1.05 inch to -1.10 inch, -1.10 inch to -1.15 inch, -1.15 inch to -1.20 inch, -1.20 inch to -1.25 inch, -1.25 inch to -1.30 inch, -1.30 inch to -1.35 inch, -1.35 inch to -1.40 inch, -1.40 inch to -1.45 inch, -1.45 inch to -1.50 inch, -1.50 inch to -1.55 inch, -1.55 inch to -1.60 inch, -1.60 inch to -1.65 inch, -1.65 inch to -1.70 inch, or -1.70 inch to -1.75 inches. In some high-MOI embodiments, the CGz location can be less than -1.0 inch, less than -1.05 inch, less than -1.10 inch, less than -1.15 inch, less than -1.20 inch, less than -1.25 inch, less than -1.30 inch, less than -1.35 inch, less than -1.40 inch, less than -1.45 inch, less than -1.50 inch, less than -1.55 inch, less than -1.60 inch, less than -1.65 inch, less than -1.70 inch, or less than -1.75 inch.

In many embodiments (high-MOI or low-MOI), the CG (160) location can be characterized by the vertical distance (defined as an axis extending through the geometric center (120) above and parallel to the loft plane (1015)) between the CG (160) and the rifling (125). In many embodiments, the CG (160) is located fairly close to the rifling (125) to provide maximum energy transfer between the club head (100) and the golf ball on shots struck at the geometric center (120). In many embodiments, the CG (160) can be located within 0.05 inches of the rifling (125). In many embodiments, the CG (160) can be located within 0.045 inches, within 0.040 inches, within 0.035 inches, within 0.030 inches, within 0.025 inches, within 0.020 inches, within 0.015 inches, or within 0.010 inches of the wire (125).

Ⅱ. Ixx/Iyy ratio

The club head has a high Ixx moment of inertia with respect to a target Iyy. An increase in Ixx with respect to a fixed target Iyy is important for improving the performance and forgiveness of the club head. Therefore, the club head has a high Ixx/Iyy ratio. In many embodiments, the club head can have an Ixx/Iyy ratio of between 0.80 and 1.0. In some embodiments, the club head can have an Ixx/Iyy ratio greater than 0.82, greater than 0.84, greater than 0.85, greater than 0.86, greater than 0.88, or greater than 0.90. As described in more detail in the examples below, the club heads can have an Ixx/Iyy ratio that is greater than 3%, greater than 5%, greater than 10%, greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, greater than 40%, greater than 45%, or greater than 50% increased over prior art club heads that focused solely on maximizing Iyy. For example, many prior art club heads have Ixx/Iyy ratios between 0.6 and 0.77. Therefore, providing a club head having an Ixx/Iyy ratio of 0.8 represents a 4% to 33% increase over prior art, depending on which prior art club head is considered. Providing an Ixx/Iyy ratio that is significantly greater than prior art (greater than 0.82, greater than 0.84, etc.) represents an even greater increase over prior art. This increased Ixx/Iyy is achieved through the cubic shaping of the clubhead and the distribution of a significant portion of the clubhead mass near the Y'-axis.

a. Cube-shaped club head shaping

As described above, a club head having a particular Iyy target can have a high Ixx/Iyy ratio for improved performance. The shaping of the club head is fundamental to efficiently maximizing the Ixx/Iyy ratio. The body shape of the club head determines where any discretionary mass can be placed. FIGS. 1-10 illustrate a club head (100) having a cube-shaped profile configured to increase the Ixx/Iyy ratio. The cube-shaped profile distributes more of the club head mass away from the X'-axis (1070) (i.e., toward the crown (110) and sole (112)) and closer to the Y'-axis (1080). Distributing mass away from the X'-axis (1070) increases the Ixx, which reduces rotation about the X'-axis (1070) at impact and balances the spin imparted to the golf ball. The distribution of mass near the Y'-axis (1080) can lower the contribution to Iyy in order to keep the club head (100) at the desired Iyy target. The cube-shaped profile provides a relatively higher body height than a flat prior art club head, effectively increasing the distance of the crown (110) and sole (112) from the X'-axis (1070). Therefore, the mass of the crown (110) and sole (112) increases the Ixx contribution without increasing the Iyy contribution. The cube-shaped profile increases Ixx without significantly increasing Iyy, thereby providing a higher Ixx/Iyy ratio. In contrast, prior art club heads seek to maximize Iyy without significantly considering Ixx. Therefore, these prior art club heads tend to place any discretionary mass deep (i.e., near the rear end (111)) and wide (i.e., near the heel (104) and toe (106)) to provide mass as far from the Y'-axis as possible.

Compared to prior art club heads that are flat and wide, the club heads of the present invention can have a body height (H _B ) that is substantially similar to the body width (W _B ) and body depth (D _B ). Compared to prior art, the cubic body dimensions can be achieved by increasing the body height (H _B ), decreasing the body width (W _B ) and body depth (D _B ), or a combination thereof, over the prior art flat designs. Referring to FIG. 2 , the club head (100) can have a body height (H _B ) (defined above) measured between the ground plane (1010) and the highest point of the crown (110). In some embodiments, the body height (H _B ) can be 2.0-3.0 inches. In some embodiments, the body height (H _B ) can be 2.0-2.1 inches, 2.1-2.2 inches, 2.2-2.3 inches, 2.3-2.4 inches, 2.4-2.5 inches, 2.5-2.6 inches, 2.6-2.7 inches, 2.7-2.8 inches, 2.8-2.9 inches, or 2.9-3.0 inches. In some embodiments, the body height (H _B ) can be greater than 2.0 inches, greater than 2.1 inches, greater than 2.2 inches, greater than 2.3 inches, greater than 2.4 inches, greater than 2.5 inches, greater than 2.5 inches, greater than 2.6 inches, greater than 2.7 inches, greater than 2.8 inches, greater than 2.9 inches, or greater than 3.0 inches. In many embodiments, the body height (H _B ) may be significantly larger than the body width (W _B ) and body depth (D _B ).

The club head (100) can further have a body width (W _B ) (as defined above) measured between the heel vertex (116) and the toe vertex (119). In some embodiments, the body width (W _B ) can be 3-5 inches. In some embodiments, the body width (W _B ) can be 3.0 inches to 3.2 inches, 3.2 inches to 3.4 inches, 3.4 inches to 3.6 inches, 3.6 inches to 3.8 inches, 3.8 inches to 4.0 inches, 4.0 inches to 4.2 inches, 4.2 inches to 4.4 inches, 4.4 inches to 4.6 inches, 4.6 inches to 4.8 inches, or 4.8 inches to 5.0 inches. In some embodiments, the body width (W _B ) can be less than 5.0 inches, less than 4.8 inches, less than 4.6 inches, less than 4.4 inches, less than 4.2 inches, less than 4.0 inches, less than 3.8 inches, less than 3.6 inches, less than 3.4 inches, less than 3.2 inches, or less than 3.0 inches. In many low-MOI embodiments, the body width (W _B ) can be significantly narrower compared to the width of prior art club heads. In many low-MOI embodiments, the body width (W _B ) can be less than 4.5 inches.

Referring to FIG. 4, the club head (100) can further have a body depth (D _B ) (defined above) measured between the leading edge (103) and the rearmost point (117) of the body (101). In some embodiments, the body depth (D _B ) can be 3-5 inches. In some embodiments, the body depth (D _B ) can be 3.0 inches to 3.2 inches, 3.2 inches to 3.4 inches, 3.4 inches to 3.6 inches, 3.6 inches to 3.8 inches, 3.8 inches to 4.0 inches, 4.0 inches to 4.2 inches, 4.2 inches to 4.4 inches, 4.4 inches to 4.6 inches, 4.6 inches to 4.8 inches, or 4.8 inches to 5.0 inches. In some embodiments, the body depth ( _DB ) can be less than 5.0 inches, less than 4.8 inches, less than 4.6 inches, less than 4.4 inches, less than 4.2 inches, less than 4.0 inches, less than 3.8 inches, less than 3.6 inches, less than 3.4 inches, less than 3.2 inches, or less than 3.0 inches. In many low-MOI embodiments, the body depth ( _DB ) can be significantly narrower compared to the depth of prior art club heads. In many low-MOI embodiments, the body depth ( _DB ) can be less than 4.0 inches.

The cubic shape of the club head (100) can be characterized by a H _B /W _B ratio, which is defined as body height (H _B ) divided by body width (W _B ). In many embodiments, the H _B /W _B ratio can be 0.50-0.75. In some embodiments, the H _B /W _B ratio can be 0.50-0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, or 0.70-0.75. In some embodiments, the H _B /W _B ratio can be greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, greater than 0.70, or greater than 0.75. By providing a high H _B /W _B ratio, the club head (100) is provided with a cubic shape that distributes mass away from the X'-axis and closer to the Y'-axis.

Similarly, the cubic shape of the club head (100) can be characterized by a H _B /D B ratio, defined as body height (H B ) divided by body depth ( _{D B} ). In many embodiments, the H _B / _{D B} ratio can be 0.5-0.75. In some embodiments, the H _B /D _B ratio can be 0.50-0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, or 0.70-0.75, and in some embodiments, the H _B /D _B ratio can be greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, greater than 0.70, or greater than 0.75. By providing a high H _B /D _B ratio, the club head (100) is provided with a cubic shape that distributes mass away from the X'-axis and closer to the Y'-axis. Therefore, the cube-shaped shape can increase Iyy beyond the target by increasing the Ixx moment of inertia without significantly contributing to Iyy. In many embodiments, the H _B /W _B ratio and the H _B /D _B ratio can be much larger than that of a flat prior art club head having an H _B /W _B ratio and an H _B /D _B ratio of less than 0.50, respectively.

The cube shape of the club head (100) can be further characterized by the sum of the H _B /W _B ratio and the H _B /D _B ratio. A perfectly cube shaped club head will have an H _B /W _B ratio and an H _B /D _B ratio each being 1. Accordingly, the perfectly cube shaped club head will have a sum of the H _B /W _B ratio and the H _B /D _B ratio being 2. In many embodiments, the club head (100) can have a sum of the H _B /W _B ratio and the H _B /D _B ratio being 1.2-1.5. In some embodiments, the club head (100) has a sum of the H _B /W _B ratio and the H B /D _B ratio greater than 1.2, greater than 1.25, greater than 1.30, greater than 1.35, greater than 1.40, greater than _1.45 , or greater than 1.50. Thus, in many embodiments, the club head has a sum of H _B /W _B ratios and H _B /D _B ratios that can be 60%-75% of a perfect cube club head. In many embodiments, the sum of the H _B /W _B ratios and the H _B /D _B ratios can be much greater than that of flat prior art club heads which tend to have sum values of less than 1.00.

Referring to FIG. 7, the cubic shape of the club head (100) can be further characterized in relation to the volume of a reference cube (125). The club head (100) can define a reference cube (125), and each side of the reference cube (125) has a length equal to the body width (W _B ). Therefore, the reference cube (125) defines a cubic reference volume equal to a cube (W _B ³ ) of the body width (W _B ). The club head (100) can define a cubic volume ratio, which is defined as the club head volume divided by the cubic reference volume. In many embodiments, the club head (100) can have a cubic volume ratio of 0.28-0.40. In some embodiments, the club head (100) can have a cubic volume ratio greater than 0.28, greater than 0.29, greater than 0.30, greater than 0.31, greater than 0.32, greater than 0.33, greater than 0.34, greater than 0.35, greater than 0.36, greater than 0.37, greater than 0.38, greater than 0.39, or greater than 0.40.

The larger the cubic volume ratio, the more cubic the shape of the club head (100). For example, a cubic club head (100) has a large body (101) relative to its body width (W _B ) and body depth (D _B ). Therefore, the cubic club head (100) effectively 'fills' a greater percentage of the reference cube (125). In contrast, many prior art club heads have a shorter, flatter profile. Therefore, such prior art club heads fill a lesser percentage of the reference cube defined by the prior art body width. Many prior art club heads having a flat body profile have a cubic volume ratio of less than 0.25.

The club head (100) may further have a gradual crown angle (172) that contributes to the cube-shaped shape. As illustrated in FIG. 6, the club head (100) has a crown axis (170) that extends between a crown transition point (174) and a rear transition point (176). The crown transition point (174) and the rear transition point (176) may both be located within the YZ plane. The crown transition point (174) may be located at a forward-most point of the crown (110) within the YZ plane. At the crown transition point (174), the curvature of the crown changes to a transition curvature between the crown (110) and the striking face (102). The rear transition point (176) may be located at a rearward-most point of the crown (110) within the YZ plane. At the rear transition point (176), the curvature of the crown changes to a transition curvature between the crown (110) and the rear end (111).

The club head (100) has a crown angle (170) measured as the acute angle between the crown axis (170) and the Y-axis (1050). In many embodiments, the club head (100) has a crown angle (170) of 75°-89°, and in some embodiments, the club head (100) has a crown angle (170) greater than 75°, greater than 76°, greater than 77°, greater than 78°, greater than 79°, greater than 80°, greater than 81°, greater than 82°, greater than 83°, greater than 84°, greater than 85°, greater than 86°, greater than 87°, greater than 88°, or greater than 89°.

The crown angle (170) within the above-mentioned range can be significantly larger than that of the prior art because the prior art club heads generally have a steeper crown angle to lower the center of gravity of the club head. The large crown angle (170) of the present club head (100) provides a crown (110) that slopes gradually downward from the front end (108) to the rear end (111). The large crown angle (170) raises the CG (160) to increase the Ixx contribution of any discretionary mass placed near the sole (112). Additionally, the larger crown angle (170) increases the distance between the mass forming the crown (110) and the X'-axis (1070), but has a minimal effect on the distance between the mass of the crown and the Y'-axis (1080). Therefore, the increased crown angle (170) increases the Ixx contribution while making the Iyy contribution negligible, thereby increasing the Ixx/Iyy ratio.

Referring to FIGS. 5 and 6, the cubic shape of the club head (100) can be further characterized by the dimensions of the striking face (102). The club head (100) can have a substantially square striking face profile, wherein the striking face height (H _SF ) and the striking face width (W _SF ) are substantially similar to each other. As illustrated in FIGS. 5 and 6 , the club head (100) can have a striking face height (H _SF ) (defined above) of 1.5-2.75 inches. In some embodiments, the striking face height (H _SF ) can be 1.5-1.75 inches, 1.75-2.0 inches, 2.0-2.25 inches, 2.25-2.50 inches, or 2.50-2.75 inches. In some embodiments, the striking face height (H _SF ) can be greater than 1.5 inches, greater than 1.75 inches, greater than 2.0 inches, greater than 2.25 inches, greater than 2.50 inches, or greater than 2.75 inches. Due to the cubic shape of the club head (100), the striking face height (H _SF ) can be significantly greater in relation to the striking face width (W _SF ) compared to the relative heights and widths of prior art art striking faces.

Additionally, the club head (100) can have a striking face width (W _SF ) (as defined above) of 2.0-3.75 inches. In some embodiments, the striking face width (W _SF ) can be between 2.0 inches and 2.25 inches, between 2.25 inches and 2.50 inches, between 2.50 inches and 2.75 inches, between 2.75 inches and 3.0 inches, between 3.0 inches and 3.25 inches, between 3.25 inches and 3.50 inches, or between 3.50 inches and 3.75 inches. In some embodiments, the striking face width (W _SF ) can be less than 3.75 inches, less than 3.50 inches, less than 3.25 inches, less than 3.0 inches, less than 2.75 inches, less than 2.50 inches, less than 2.25 inches, or less than 2.0 inches. Due to the cubic shape of the club head (100), the striking face width (W _SF ) can be significantly narrower than the shorter and wider striking faces of prior art. In many low-MOI embodiments, the striking face width (W _SF ) can be less than 3.0 inches.

The substantially square profile of the striking surface (102) can be characterized by a striking surface aspect ratio. The striking surface aspect ratio is defined as the ratio of the striking surface height (H _SF ) divided by the striking surface width (W _SF ). In many embodiments, the striking surface aspect ratio can be 0.70-0.90. In some embodiments, the striking surface aspect ratio can be from 0.70 to 0.72, from 0.72 to 0.74, from 0.74 to 0.76, from 0.76 to 0.78, from 0.78 to 0.80, from 0.80 to 0.82, from 0.82 to 0.84, from 0.84 to 0.86, from 0.86 to 0.88, or from 0.88 to 0.90, and in some embodiments, the striking surface aspect ratio can be greater than 0.70, greater than 0.72, greater than 0.74, greater than 0.76, greater than 0.78, greater than 0.80, greater than 0.82, greater than 0.84, greater than 0.86, greater than 0.88, or greater than 0.90. The club head (100) has a larger aspect ratio than the short, flat striking face of prior art club heads. The substantially square profile of the striking face (102) corresponds to the cube-shaped shape of the overall club head profile, all of which contribute to an increase in the Ixx/Iyy ratio.

The club head (100) can have a club head volume suitable for a driver type club head. In high-MOI embodiments, the club head (100) can have a volume of 350 g*cm2 to 460 g*cm2. In some high-MOI embodiments, the club head (100) can have a volume of 350 g*cm2 to 370 g*cm2, 370 g*cm2 to 390 g*cm2, 390 g*cm2 to 410 g*cm2, 410 g*cm2 to 430 g*cm2, 430 g*cm2 to 450 g*cm2, or 450 g*cm2 to 460 g*cm2. In some high-MOI embodiments, the club head (100) can have a volume greater than 350 g*cm2, greater than 370 g*cm2, greater than 390 g*cm2, greater than 410 g*cm2, greater than 430 g*cm2, greater than 450 g*cm2, or greater than 460 g*cm2.

In low-MOI embodiments, the club head volume can be significantly lower than typical prior art club heads. A larger club head volume will naturally increase Iyy. When the Iyy target is low, providing a smaller club head volume increases the ability to place discretionary mass in a manner that increases Ixx and provides a higher Ixx/Iyy ratio. In many low-MOI embodiments, the club head (100) can have a volume of 200-350 cm3. In some low-MOI embodiments, the club head (100) can have a volume of 200-220 cm3, 220-240 cm3, 240-260 cm3, 260-280 cm3, 280-300 cm3, 300-320 cm3, 320-340 cm3, or 340-350 cm3. In some low-MOI embodiments, the club head (100) can have a volume of less than 350 cm3, less than 340 cm3, less than 320 cm3, less than 300 cm3, less than 280 cm3, less than 260 cm3, less than 240 cm3, less than 220 cm3, or less than 200 cm3.

As characterized above, the cubic shape of the club head body (101) provides an increased Ixx/Iyy ratio to the club head (100). The unique shape of the club head may also affect the aerodynamic characteristics of the club head. Overall, in many low-MOI embodiments, the smaller size of the club head (100) results in improved aerodynamic characteristics. As described above, low-MOI embodiments generally have a smaller club head volume, which is associated with smaller body dimensions (body height (H _B ), body depth (D _B ), and body width (W _B )), smaller surface area, and smaller projected area. Thus, the smaller club head profile reduces the amount of drag applied to the club head (100) during the swing, allowing the player to swing faster and hit the golf ball farther. However, in some embodiments, a more cubic body shape may provide less aerodynamic performance than a flatter club head of the same volume. To compensate for any increased drag associated with the cube-shaped body shape, the club head (100) may additionally include one or more aerodynamic features or characteristics, such as turbulators or aerodynamic transition curvatures, all of which are described in more detail in the “Additional Features” section below. Thus, the club head (100) achieves a balance between the Ixx/Iyy ratio and aerodynamics.

Ⅲ. Club head mass distribution

In addition to the shape and body dimensions of the club head (100), the effect of maximizing the Ixx/Iyy ratio depends on the mass distribution of the club head. In particular, achieving a high Ixx/Iyy ratio relies on disposing most of the club head's discretionary mass close to the Y'-axis (1080), but away from the X'-axis (1070). In doing so, the discretionary mass contributes significantly to increasing Ixx without raising Iyy above a target value. Thus, the club head constitutes a significant portion of the total mass around the Y'-axis (1080). In contrast, many prior art club heads focus solely on maximizing Iyy rather than the Ixx/Iyy ratio, and thus seek to dispose all of the discretionary mass as far from the Y'-axis as possible.

The mass distribution of a club head can be characterized by the amount of club head mass located within a center mass area (130). Referring to FIGS. 8 and 9, the center mass area (130) is defined as an imaginary cylinder that is centered about the Y'-axis (1080) and extends throughout the club head body (101) from the crown (110) to the sole (112). The size of the center mass area (130) is determined by a center mass area radius (R _CMZ ). The center mass radius (R _CMZ ) can be from 0.50 inches to 1.5 inches measured perpendicular to the Y'-axis (1080). In some embodiments, the center mass zone radius can be 0.50 inches, 0.55 inches, 0.60 inches, 0.65 inches, 0.70 inches, 0.75 inches, 0.80 inches, 0.85 inches, 0.90 inches, 0.95 inches, 1.00 inches, 1.05 inches, 1.10 inches, 1.15 inches, 1.20 inches, 1.25 inches, 1.30 inches, 1.35 inches, 1.40 inches, 1.45 inches, or 1.50 inches. In many embodiments, the center mass zone radius (R _CMZ ) is 0.75 inches. The greater the percentage of club head mass located within the center mass zone (130), the less that mass contributes to an increase in Iyy while still providing a significant increase in Ixx. Therefore, the effect of the club head on increasing the Ixx/Iyy ratio can be directly related to the amount of club head mass located within the center mass area (130).

In many embodiments, the mass distribution of the club head (100) can be characterized by the percentage of the total club head mass that is defined within the center mass region (130). In some embodiments, 10%-50% of the total club head mass can be located within the center mass region (130). In some embodiments, greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, greater than 40%, greater than 45%, or greater than 50% of the total club head mass can be located within the center mass region (130). The percentage of the total club head mass located within the center mass region (130) is highly dependent on the selected center mass region radius (R _CMZ ). In many embodiments, the percentage of mass within the center mass region (130) can be evaluated considering a center mass region radius (R _CMZ ) of 0.75 inches. In many embodiments, greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, or greater than 40% of the total mass of the club head may be located within a center mass zone (130) of a radius (R _CMZ ) of 0.75 inches.

In some embodiments, the mass distribution of the club head can be further characterized by the size of a center mass region (130) that contains a particular percentage of the total club head mass. For example, in some embodiments, 30% of the total club head mass may be located within a center mass zone (130) of a center mass zone radius (R CMZ ) (measured perpendicular to the Y'-axis (1080)) less than 1.50 inches, less than 1.45 inches, less than 1.40 inches, less than 1.35 inches, less than 1.30 inches, less than 1.25 inches, less than 1.20 inches, less than 1.15 inches, less than 1.10 inches, less than 1.05 inches, less than 1.00 inches, less than 0.95 inches, less than 0.90 inches, less than 0.85 inches, less than 0.80 inches, less than 0.75 _inches , less than 0.70 inches, less than 0.65 inches, less than 0.60 inches, less than 0.55 inches, or less than 0.50 inches. Therefore, the club head (100) has a small center mass area (130) containing a significant portion (30%) of the total club head mass. Accordingly, a significant portion of the club head mass is positioned close to the Y'-axis (1080), increasing the Ixx/Iyy ratio.

Additionally, the mass distribution of the club head can be further characterized by a first mass distribution index (MD ₁ ). The first mass distribution index (MD ₁ ) quantifies the efficiency of distributing mass near the Y'-axis (1080) by relating the proportion of total club head mass within a center mass region (130) to the size of the center mass region (130). The first mass distribution index (MD ₁ ) is determined as follows:

Here, M _CMZ is the mass within the center mass region (130), M _T is the total club head mass, and R _CMZ is the center mass region radius within the aforementioned radius range. In many embodiments, the club head (100) can have a first mass distribution index (MD ₁ ) greater than 0.10. In some embodiments, the club head (100) can have a first mass distribution index (MD ₁ ) of 0.10-0.15, 0.15-0.20, 0.20-0.25, 0.25-0.30, 0.30-0.35, 0.35-0.40, 0.40-0.45, or 0.45-0.50. In some embodiments, the club head (100) can have a first mass distribution index (MD ₁ ) greater than 0.10, greater than 0.15, greater than 0.20, greater than 0.25, greater than 0.30, greater than 0.35, greater than 0.40, greater than 0.45, or greater than 0.50. A greater club head mass ratio within a center mass region (130) and a smaller center mass region radius (R _CMZ ) of the center mass region (130) increase the first mass distribution index and more effectively increase the Ixx/Iyy ratio of the club head (100).

Additionally, the mass distribution of the club head can be further characterized by a second mass distribution index (MD ₂ ). The second mass distribution index (MD ₂ ) represents the amount of mass disposed near the Y'-axis (1080) with respect to the volume of the club head (100). The second mass distribution index (MD ₂ ) is determined as follows:

Here, M _CMZ is the mass within the center mass region (130), M _T is the total club head mass, and V is the volume of the club head. In many embodiments, the club head (100) can have a second mass distribution index (MD ₂ ) greater than 0.5. In some embodiments, the club head (100) can have a second mass distribution index (MD ₂ ) of 0.50-0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, 0.70-0.75, 0.75-0.80, 0.80-0.85, 0.85-0.90, 0.90-0.95, or 0.95-1.00. In some embodiments, the club head (100) can have a second mass distribution index (MD 2 ) greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, greater than 0.70, greater than 0.75, greater than 0.80, greater than 0.85, greater than 0.90, greater than 0.95, or greater than _1.00 . Since the club head (100) comprises a significantly larger proportion of mass and a significantly smaller volume within the center mass region (130) compared to prior art, the second mass distribution index (MD ₂ ) will be significantly larger compared to prior art.

Additionally, the mass distribution of the club head can be further characterized by a third mass distribution index (MD3). The third mass distribution index ( _MD3 ) represents the amount of mass positioned close to the Y'-axis (1080) relative to the club head Iyy. The third mass distribution index ( _MD3 ) is determined as follows:

Here, M _CMZ is the mass within the center mass region (130), and M _T is the total club head mass. In many embodiments, the club head (100) may have a third mass distribution index (MD ₃ ) greater than 0.050. In some embodiments, the club head (100) can have a third mass distribution index (MD 3 ) of 0.050-0.060, 0.060-0.070, 0.070-0.080, 0.080-0.090, 0.090-0.100, 0.100-0.110, 0.110-0.120, 0.120-0.130, 0.130-0.140, 0.140-0.150, 0.150-0.160, 0.160-0.170, 0.170-0.180, 0.180-0.190, or 0.190-0.200, and in some embodiments, the club head (100) can have a third mass distribution index (MD ₃ ) of greater than 0.050, The third mass distribution index (MD 3 ) can be greater than 0.060, greater than 0.070, greater than 0.080, greater than 0.090, greater than 0.100, greater than 0.110, greater than 0.120, greater than 0.130, greater than 0.140, greater than 0.150, greater than 0.160, greater than 0.170, greater than 0.180, greater than 0.190, or greater than _0.200 . Since the club head (100) has a significantly larger proportion of mass within the center mass region (130) and a significantly lower Iyy target value compared to prior art, the third mass distribution index (MD ₃ ) will be significantly larger compared to prior art.

a. Mass pad

In many embodiments, the club head may include one or more mass pads strategically positioned to increase the Ixx/Iyy ratio. The one or more mass pads may be integrally formed with a portion of the sole (112), a portion of the crown (110), a portion of the heel (104), a portion of the toe (106), or any combination thereof. As illustrated in FIG. 10 , the club head (100) includes a sole mass pad (140) integrally formed with an interior surface of the sole (112) and extending into an interior cavity (107). Similarly, the club head (100) illustrated in FIG. 10 includes a crown mass pad (142) integrally formed with an interior surface of the crown (110) and extending into an interior cavity (107). In other embodiments, the club head (100) may include any combination of crown mass pads, sole mass pads, or other mass pads located elsewhere on the body (101). Although the sole mass pad (140) and crown mass pad (142) of the present embodiment are illustrated and described as being integral with the body (101), in other embodiments, one or more of the mass pads may be separate members that are joined to the club head body (101) via welding, brazing, mechanical bonding, adhesive bonding, or any other suitable means.

In many embodiments, the sole mass pad (140) and the crown mass pad (142) can be positioned at or near the Y'-axis (1080) such that all or most of the sole mass pad (140) and/or the crown mass pad (142) fits within the center mass region (130). Thus, the sole mass pad (140) and the crown mass pad (142) provide significant contributions to Ixx while making minor contributions to Iyy, thereby increasing the Ixx/Iyy ratio. In many embodiments, such as the exemplary embodiment of FIG. 10, the sole mass pad (140) and/or the crown mass pad (142) can be intersected by the Y'-axis. The proximity of any mass pad (i.e., the sole mass pad (140) and/or the crown mass pad (142)) to the Y'-axis can be characterized by the size of the center mass region (130) that bounds the entire mass pad (as described above). For example, in some embodiments, the sole mass pad (140) and/or the crown mass pad (142) can be entirely defined within a center mass region (130) of a center mass region radius (R _CMZ ) of less than 2.00 inches, less than 1.75 inches, less than 1.50 inches, less than 1.25 inches, less than 1.00 inches, less than 0.75 inches, less than 0.50 inches, or less than 0.25 inches. The smaller the center mass region radius (R _CMZ ) that bounds the entire mass pad, the more efficient the mass pad is at increasing the Ixx/Iyy ratio. A mass pad defined within a small center mass region (130) contributes more to Ixx than to Iyy compared to a similar mass pad of the same mass that does not fit within the center mass region (130). For example, a 20 g mass pad that fits completely within a center mass area (130) of 0.75 inch radius (R _CMZ ) will have a smaller Iyy contribution (and therefore a higher Ixx/Iyy ratio) than a 20 g mass pad that fits only partially within the center mass area (130) of 0.75 inch radius (R _CMZ ).

The crown mass pad (140) and/or sole mass pad (142) may be positioned centrally of the crown (110) and sole (112), respectively. In many embodiments, at least a portion of the crown mass pad (140) and/or sole mass pad (142) may intersect the YZ plane (described above as a vertical plane aligned with both the Y-axis (1050) and the Z-axis (1060). In some embodiments, the crown mass pad (140) and/or sole mass pad (142) may be positioned entirely within the middle 50% of the body depth (D _B ). In some embodiments, the crown mass pad (140) and/or sole mass pad (142) may be positioned entirely within the middle 45% of D _B , the middle 40% of D _B , the middle 35% of D _B , the middle 30% of D _B , the middle 25% of D _B , or the middle 20% of D _B . In some embodiments, the crown mass pad (140) and/or the sole mass pad (142) may be positioned entirely within the middle 50% of the body width (W _B ). In some embodiments, the crown mass pad (140) and/or the sole mass pad (142) may be positioned entirely within the middle 45% of W _B , the middle 40% of W _B , the middle 35% of W _B , the middle 30% of W _B , the middle 25% of W B , or the middle 20% of W _B . In many embodiments _, the forward-most point of the crown mass pad (140) and/or the sole mass pad (142) may be spaced rearward of the leading edge (103) by a significant percentage of the body depth (D _B ). In some embodiments, the forwardmost point of the crown mass pad (140) and/or the sole mass pad (142) may be spaced rearward of the leading edge (103) by a distance of at least 10%, at least 15%, at least 20%, or at least 25% of the body depth (D _B ).

In many embodiments, the crown mass pad (140) and the sole mass pad (142) may comprise a significant portion of the total club head mass. In many embodiments, the crown mass pad (140) may be larger than the sole mass pad (142) to maintain the location of the CG (160) lower and/or closer to the ridge (125). In many embodiments, the crown mass pad (140) may have a mass of 5-30 g. In some embodiments, the crown mass pad (140) may have a mass of 5-10 g, 10-15 g, 15-20 g, 20-25 g, or 25-30 g. In some embodiments, the crown mass pad (140) may have a mass greater than 5 g, greater than 10 g, greater than 15 g, greater than 20 g, greater than 25 g, or greater than 30 g.

In many embodiments, the sole mass pad (142) can have a mass of 10-60 g. In some embodiments, the sole mass pad (142) can have a mass of 10-15 g, 15-20 g, 20-25 g, 25-30 g, 30-35 g, 35-40 g, 40-45 g, 45-50 g, 50-55 g, or 55-60 g. In some embodiments, the sole mass pad (142) can have a mass of greater than 5 g, greater than 10 g, greater than 15 g, greater than 20 g, greater than 25 g, greater than 30 g, greater than 35 g, greater than 40 g, greater than 45 g, greater than 50 g, greater than 55 g, or greater than 60 g.

In many embodiments, the club head (100) can have a mass pad ratio defined as the mass of the sole mass pad (142) divided by the mass of the crown mass pad (140). In many embodiments, the mass pad ratio can be 0.25-1.5. In some embodiments, the mass pad ratio can be 0.25-0.50, 0.50-0.75, 0.75-1.0, 1.0-1.25, or 1.25-1.5. In some embodiments, the mass pad ratio can be greater than 0.25, greater than 0.50, greater than 0.75, greater than 1.0, greater than 1.25, or greater than 1.5. In some embodiments, the mass-pad ratio can be less than 1.5, less than 1.4, less than 1.3, less than 1.2, less than 1.1, less than 1.0, less than 0.9, less than 0.8, less than 0.7, less than 0.6, less than 0.5, less than 0.4, less than 0.3, or less than 0.25. Providing the crown mass pad (140) and the sole mass pad (142) with significant mass, but with the crown mass pad (140) being larger than the sole mass pad (142), can provide a high Ixx/Iyy ratio and a desirable, low CG (160) location for the club head (100).

b. Absence of weight

In addition to distributing a greater portion of the club head mass near the Y'-axis (1080) to increase the Ixx/Iyy ratio, the Ixx and Iyy can be controlled through the use of one or more weight members (145). In some embodiments, the club head (100) can include at least one weight member (145) individually formed and attached to the body (101). The weight member (145) can be attached to any portion of the body (101). The weight member (145) can be attached to the crown (110), the sole (112), the heel (104), the toe (106), the rear end (111) or proximate thereto, the front end (108) proximate thereto, or any combination thereof. In many embodiments, the weight member (145) can be removably coupled to the body (101) via mechanical fasteners, such as using threaded fasteners or some other retaining means. In other embodiments, the weight member (145) may be permanently or indetachably attached to the body (101) via welding, brazing, adhesive bonding, or any other suitable means. The weight member (145) may comprise a material having a density greater than the density of the material used to form the body (101). As such, the weight member (145) provides a high concentration of mass that can be positioned to provide desirable mass characteristics to the club head (100). In many embodiments, the weight member (145) may be formed of a high-density material, such as titanium, tungsten, steel, or any suitable alloy thereof.

In some embodiments, as illustrated in FIGS. 9 and 10, the club head (100) may include a weight member (145) attached to the body (101) between the rear end (111) and the sole (112). A low rearward position of the weight member (145) provides a desirable "low rearward" CG location and increases the overall club head MOI. The rearmost position of the weight member (145) provides a significant contribution to both Ixx and Iyy because of the large horizontal distance between the weight member (145) and the X'-axis (1070) and Y'-axis (1080). However, in many embodiments, the weight member (145) may be configured such that its contribution to Ixx is greater than to Iyy, thereby increasing the Ixx/Iyy ratio. To provide a high Ixx/Iyy ratio, the weight member (145) can also be positioned as far toward the bottom of the sole (112) as possible to maximize its contribution to the Ixx increase. By lowering the weight member (145) with respect to the CG (160), the weight member (145) is positioned further from the X'-axis (1070) in the vertical direction, but not further from the Y'-axis (1080) extending vertically.

To characterize the relative contributions of the weight member (145) to Ixx and Iyy, the club head (100) can have a ratio between a weight member height (E _W ) and a weight member depth (D _W ). As illustrated in FIG. 10 , the weight member height (E _W ) is defined as the distance between the club head CG (160) and the weight member center of gravity (147), measured parallel to the Y'-axis (1080). The weight member depth (D _W ) is defined as the distance between the club head CG (160) and the weight member center of gravity (147), measured parallel to the Z'-axis (1090).

In many embodiments, the club head (100) can have an E _W /D _W ratio of 0.30-0.60. In some embodiments, the E _W /D _W ratio can be 0.30-0.35, 0.35-0.40, 0.45-0.50, or 0.55-0.60. In some embodiments, the club head can have an E _W /D _W ratio greater than 0.3, greater than 0.35, greater than 0.40, greater than 0.45, greater than 0.50, greater than 0.55, or greater than 0.60. As the E _W /D _W ratio increases, the Ixx contribution of the weight member (145) increases relative to the Iyy contribution of the weight member (145). Thus, a club head (100) having a relatively high E _W /D _W ratio also has an increased Ixx/Iyy ratio.

Additionally, the MOI of the weight member (145) can be characterized by its mass relative to the total club head mass (hereinafter referred to as the "weight member mass ratio"). A weight member (145) having a greater ratio of total club head mass will have a greater effect on the moment of inertia. In many embodiments, the weight member (145) can be 10-30% of the total club head mass. In some embodiments, the weight member can be 10-15%, 15-20%, 20-25%, or 25-30% of the total club head mass.

The weight member mass ratio and the E _W /D _W ratio can characterize how the weight member (145) contributes to an increase in the Ixx/Iyy ratio. A heavier weight member (145) (higher mass ratio) located significantly below the CG (160) and near the Y'-axis (1080) (higher E _W /D _W ratio) provides a higher Ixx/Iyy ratio. The sum of the weight member mass ratio and the E _W /D _W ratio can be 0.4-0.9. In some embodiments, the sum of the weight absence mass ratio and the E _W /D _W ratio can be 0.4-0.45, 0.45-0.50, 0.50-0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, 0.70-0.75, 0.75-0.80, 0.80-0.85, or 0.85-0.90.

c. Absence of adjustable weight

FIG. 11 illustrates a club head (200) having an adjustable weight member (205) that can be affixed to any of a plurality of attachment points (230) within a channel (210), each of which will support a unique shot shape. The club head (200) can include a weight channel (210) recessed in a rear end (211) of a club head body (201), the weight channel (210) being configured to receive the adjustable weight member (205). The adjustable weight member (205) is affixed within the weight channel (210) by a mechanical fastening means, such as a screw (215). The weight channel (210) can be recessed within the club head (200) such that a substantial portion of the adjustable weight member (205) is recessed within the weight channel (210) and does not extend beyond the perimeter of the club head (200). In many embodiments, as illustrated in FIG. 11, the weight channel (210) may have a generally curved shape that follows the curvature of the club head (200). The weight channel (210) may also include a plurality of rectilinear sections that are inclined toward one another.

The weight channel (210) further includes a plurality of attachment points (230) for securing the adjustable weight member (205) to the weight channel (210) at individual locations. One of the attachment points (230) may be a neutral attachment point (231) that is substantially centered about the club head (200) in the heel-toe direction. The neutral attachment point (231) assists in a generally straight ball flight. The club head (200) may further include a heel-side attachment point (232) positioned on the heel side of the neutral attachment point (231). The heel-side attachment point (232) positions the adjustable weight member (205) toward the heel (204) side of the club head (200) to move the CG (260) toward the heel side and assist in a draw type golf shot. The club head (200) may further include a toe-side attachment point (233) located on the toe side of the neutral attachment point (231). The toe-side attachment point (233) positions the adjustable weight member (205) on the toe side of the club head (200) to move the CG (260) to the toe side and support a fade type golf shot.

In many embodiments, the weight member (205) can have a mass of 1-40 g. In some embodiments, the mass of the weight member (1090) is in the range of 1-5 g, 5-10 g, 10-15 g, 15-20 g, 20-25 g, 25-30 g, 30-35 g, or 35-40 g.

Having the weight members (205) positioned at the rear end (211) of the club head (200) with their attachment points (230) relatively close to each other means that when the mass of the weight members (205) is selected to be at the lower end of its range (e.g., 5 g), they will have a relatively small contribution to the CG and MOI of the club head (200). By selecting a heavier weight member (205) with a mass at the higher end of its range (e.g., 40 g), the weight members can still have a relatively large contribution to the CG and MOI of the club head (200) while having a relatively small distance between their attachment points (230). In this manner, the design of the adjustable weight members (205) can allow the weight channels (210) to remain compact while providing significant shot shaping capability. Another advantage of the compact weight channel (210) is that the lightweight structure of the weight channel (210) allows for additional discretionary mass to be placed elsewhere on the club head (200).

d. Multi-material composition

In some embodiments, as illustrated in FIGS. 12-14, the club head (300) may have a multi-material configuration. In such embodiments, the body (301) may include at least a first component (350) formed of a metallic material, such as a composite material, and a second component (352) formed of a non-metallic material. The non-metallic second component (352) may form at least a portion of the crown (310), at least a portion of the heel (304), at least a portion of the toe (306), at least a portion of the sole (312), or any combination thereof. Providing the club head (300) with a body (301) formed at least partially of a non-metallic component (352) creates some discretionary mass that can be redistributed throughout the club head (300) to increase the Ixx/Iyy ratio. By providing at least a portion of the body (301) formed by the non-metallic second component (352), additional arbitrary mass can be placed within the central mass region (330) or used to increase the mass of any mass pad or weight member described above.

As illustrated in FIG. 12, in many embodiments, the club head (300) may include a non-metallic second component (352) that forms a majority of the surface of the crown (310). In the illustrated embodiment, the body (301) includes a first component (350) that forms a forward portion of the crown (310) proximate the striking face (302). The second component (352) may form the remainder of the crown. In the illustrated embodiment, the second component (352) may form a “wrap-around” design (as illustrated in FIG. 14) where the second component (352) wraps around the heel (304) and toe (306) and wraps around the sole (312). In many embodiments, the second component (352) does not wrap around the rear edge (309) of the club head (300).

As illustrated in FIG. 12, the second component (352) includes a second component rear edge (356) that is defined within the perimeter of the crown (310) and does not extend above the club head rear edge (309) or the sole (312). In many embodiments, as illustrated in FIG. 12, the second component rear edge (356) may be positioned substantially proximate the club head rear edge (309). In other embodiments, referring to FIG. 13, the second component rear edge (356) may be spaced a substantial distance from the club head rear edge (309). In the exemplary embodiment of FIG. 13, the first component (350) forms a rear lip (359) that extends forward from the club head rear edge (309) to form a rear portion of the crown (310). The second component (352) may include a cutout portion (357) corresponding to the shape of the rear lip (359), with the second component rear edge (356) contacting the front edge of the rear lip (359). This configuration positions the rear connection between the first component (350) and the second component (352) away from the club head rear edge (309). In many cases, this can provide both manufacturing and durability advantages by providing sufficient space between the non-metallic second component (352) and the weight insert (345) positioned near the club head rear end (309) (see FIG. 14 ). Manufacturers often require a significant gap between such rear weight members (345) and the non-metallic component so that they can cast the shape of the weight member support structure.

Referring to FIG. 14, the second component (352) surrounds the heel (304) and the toe (306) and forms a portion of the sole (312). The second component (352) may include a second component heel portion (353) forming at least a portion of the sole (312) near the heel (304) and a second component toe portion (354) forming at least a portion of the sole (312). In the illustrated embodiment, the first component (350) forms a majority of the sole (312). As described above, the club head (300) may include a weight member (345) positioned at the sole (312) near the club head rear edge (309) to provide a lower rear CG (360) location - thereby increasing the MOI.

The amount of non-metallic material forming the body (301) can be characterized by the percentage of surface area of the crown (310) that is formed by the second component (352) and/or the percentage of surface area of the sole (312) that is formed by the second component (352). In some embodiments, the second component (352) can form at least 50% of the surface area of the crown (310). In some embodiments, the second component (352) can form at least 60%, at least 70%, at least 80%, or at least 90% of the surface area of the crown (310). In some embodiments, the second component (352) can form at least 10% of the surface area of the sole (312). In some embodiments, the second component (352) can form at least 15%, at least 20%, at least 25%, or at least 30% of the surface area of the sole (312). The sum of the ratios of the sole and crown in the composite determines the sole-crown composite ratio. The higher the proportion of the body (301) formed by the non-metallic second component (352), the more discretionary mass can be strategically distributed to increase the Ixx/Iyy ratio.

The wrap-around design of the non-metallic second component (352) can assist in distributing mass within the center mass area (130) to provide a higher Ixx/Iyy ratio. In many embodiments, the second component heel portion (353) and the second component toe portion (354) can form only a portion of the sole (312) located near the perimeter of the club head and outside the center mass area (130). In many embodiments, the second component heel portion (353) and the second component toe portion (354) can not extend within the center mass area (130) having a radius (R _CMZ ) of 0.75 inches. This configuration removes mass from a portion of the sole (312) outside the center mass area (130) without removing any mass from the portion of the sole that is within the center mass area (130). Any residual mass generated by removing mass from the sol (312) can be redistributed within the central mass region (130) to increase the Ixx/Iyy ratio.

e. Lightweight shaft receiving structure

In some embodiments, referring to FIG. 24, the club head (400) may include a lightweight shaft-receiving structure (478) that creates optional discretionary mass. The discretionary mass may be assigned to a portion of the club head (400) that increases the Ixx/Iyy ratio. By providing the lightweight shaft-receiving structure (478), additional discretionary mass may be placed within the center mass area (430) or may be used to increase the mass of any of the mass pads or weight elements described above.

Referring to FIG. 24, in some embodiments, the club head (400) may include an adjustable shaft-receiving mechanism. The adjustable shaft receiving mechanism may be used to adjust the loft angle and/or lie angle for a particular player. The adjustable shaft receiving mechanism may be similar to that described in U.S. Patent Application No. 15/003,494, filed January 21, 2016, which is hereby incorporated by reference in its entirety as is U.S. Patent No. 9,868,035, issued January 16, 2018; and U.S. Patent Application No. 17/304,836, filed January 25, 2021, which is hereby incorporated by reference in its entirety as is U.S. Patent No. 11,607,590, issued March 21, 2023.

An adjustable shaft receiving mechanism includes a shaft sleeve (480) configured to receive a golf club shaft (not shown) and held within a hosel (405) by a fastener (482). The shaft sleeve (480) and the hosel (405) are configured with corresponding geometries such that the shaft sleeve (480) can be removably rotated into a plurality of different configurations. Rotating the shaft sleeve (480) between the different configurations can provide loft angle (10) and/or lie angle (15) adjustability for the club head (400). Referring to FIG. 24, a lightweight shaft receiving structure (478) receives the shaft sleeve (480) with minimal structural mass. The shaft sleeve (480) is at least partially exposed to the interior cavity (407). In this embodiment, the shaft sleeve (480) is retained within the club head (401) by a structure that forms at least a portion of the exterior of the club head body (400), rather than being retained by an internal structure such as an inner hosel tube or hosel wall. That is, the shaft sleeve (480) is primarily supported and retained by the partial body (401). In many embodiments, the shaft receiving structure (478) includes an upper portion and a lower portion. In this embodiment, the shaft sleeve (480) is secured only at the upper portion (488) and the lower portion (489). The shaft sleeve (480) is inserted through the hosel bore opening (484) and is retained at the upper portion by the hosel wall (486). The shaft sleeve (480) can be secured to the club head (400) using a fastener (482).

The lightweight shaft receiving structure (478) can generate any discretionary mass of 3-12 g compared to prior art shaft receiving structures in which the shaft sleeve is concealed from the internal cavity by a support structure, such as a hosel tube or an internal hosel wall. In some embodiments, the lightweight shaft receiving structure (478) can generate any discretionary mass of 3-5 g, 4-6 g, 5-7 g, 6-8 g, 7-9 g, 8-10 g, 9-11 g, or 10-12 g compared to prior art shaft receiving structures. In some embodiments, the lightweight shaft receiving structure (478) can generate any discretionary mass of greater than 3 g, greater than 4 g, greater than 5 g, greater than 6 g, greater than 7 g, greater than 8 g, greater than 9 g, or greater than 10 g compared to prior art shaft receiving structures. Removing the redundant support structure to reduce the mass of the shaft receiving structure (478) allows the excess mass to be reallocated to other portions of the club head (400), thereby increasing the Ixx/Iyy ratio. In particular, because the shaft receiving structure (478) is positioned proximate the heel (404), the mass forming the shaft receiving structure (478) is generally located outside the center mass area (430). Reducing the mass of the shaft receiving structure (478) by removing the redundant support structure is particularly effective in increasing the Ixx/Iyy because it removes mass located outside the center mass area (430) and redistributes that mass within the center mass area (430).

Ⅳ. Optimization of Bulge and Roll

As described above, the club head (100) may further have bulge and roll curvatures specifically tailored to the club head characteristics to provide enhanced performance and forgiveness. Thus, the club head may satisfy one or more bulge radius or roll radius relationships to maximize distance and forgiveness. The bulge and roll radius relationships may depend on factors such as CG location, MOI, coefficient of restitution (COR), etc. Optimized bulge and roll curvatures may be particularly useful in low-MOI club heads, because the increased forgiveness due to bulge and roll curvatures may compensate for the loss of forgiveness associated with a low target Iyy. In some embodiments, as can be seen in the examples below, providing a low-MOI club head (100) with optimized bulge and roll radii may provide enhanced forgiveness compared to a high-MOI club head with a reference bulge and roll radii (i.e., a bulge and roll radii that is not optimized for the club head characteristics).

The striking face (102) of the club head (100) has a bulge radius that provides forgiveness for toe-side and heel-side mis-hits. When a golf ball is mis-hit near the heel (104) or toe (106), the club head (100) rotates about the Y'-axis (1080). Rotation about the Y'-axis (1080) creates a gearing effect between the striking face (102) and the golf ball, which imparts side spin to the golf ball. In the case of a toe-side mis-hit, the gearing side spin causes the golf ball to be drawn from the toe-side toward the heel-side. Conversely, in the case of a heel-side mis-hit, the gearing side spin causes the golf ball to fade from the heel-side toward the toe-side. The bulge curvature counteracts the effect of gearing side spin by 1) changing the starting direction of a golf shot and 2) changing the intensity of the gearing effect. For example, a narrow bulge radius will launch the golf ball further off-center and reduce the gearing effect, while a wide bulge radius will launch the golf ball closer to center and increase the gearing effect.

The Iyy and CG locations of the club head each affect the amount of rotation at impact and the gearing effect on a heel-side or toe-side mis-hit, respectively. Therefore, each should be considered when determining the optimal bulge radius. The lower the Iyy, the more the club head twists in the heel-toe direction, which increases the gearing side spin. A further rearward CG location also increases the heel-toe rotation of the club head on a mis-hit, away from the geometric center (120). The club head (100) has a bulge radius that appropriately considers the Iyy and CG locations. The optimal bulge radius balances the starting line and the gearing effect to provide the correct amount of side spin to return the golf ball to the target line. Additionally, the coefficient of restitution (hereinafter referred to as 'COR') of the club head may play a role in determining the optimal bulge radius. A club head with a low COR will experience reduced speed on a mis-hit. It may be desirable to provide a wider bulge radius in such low-COR club heads. A wider bulge radius reduces the oblique impact between the striking face (102) and the golf ball on heel-side or toe-side mis-hits, thus maintaining higher speed. In high COR club heads, the bulge radius can be narrower to prioritize correction of gearing spin over maintenance of speed, since the high COR naturally maintains speed on mis-hits.

In many embodiments, the bulge radius can be determined via computer simulations that take into account a range or values of club head MOI (both Ixx and Iyy) and CG locations. In many embodiments, the computer simulations can be performed for various swing speeds, face transfer angles, and/or impact locations of the striking face (102). In many embodiments, a range of Ixx and a range of Iyy can be selected, and the bulge radius can be calculated as a function of the CG location of the club head (100) within the ranges of Ixx and Iyy. In some embodiments, the club head (100) satisfies relationship 1 for Iyy in the range of 2000 g*cm2 to 3200 g*cm2 and Ixx in the range of 1480 g*cm2 to 2370 g*cm2.

For example, in many embodiments, the club head (100) may satisfy relationship 1 and have Iyy of less than 3500 g*㎠, less than 3200 g*㎠, less than 3000 g*㎠, less than 2800 g*㎠, or less than 2600 g*㎠. For example, in many embodiments, the club head (100) may satisfy relationship 1 and have Ixx of less than 2600 g*㎠, less than 2500 g*㎠, less than 2400 g*㎠, less than 2200 g*㎠, less than 2000 g*㎠, less than 1800 g*㎠, or less than 1500 g*㎠.

Additionally, the striking face (102) of the club head (100) has a roll radius that provides forgiveness for crown-side and sole-side mis-hits. When a golf ball is mis-hit near the crown (110) or sole (112), the club head (100) rotates about the X'-axis (1080). The rotation about the X'-axis (1070) creates a gearing effect between the striking face (102) and the golf ball that changes the natural backspin of the golf ball. For crown-side mis-hits, the gearing effect decreases the backspin of the golf ball. Conversely, for sole-side mis-hits, the gearing effect increases the backspin of the golf ball. The roll curvature counteracts the gearing effect on backspin by 1) changing the launch angle of the golf shot and 2) changing the strength of the gearing effect. For example, a narrow roll radius will reduce the gearing effect by launching the golf ball higher on crown-side miss-hits and lower on sole-side miss-hits, while a wide roll radius will increase the gearing effect by launching the golf ball closer to the launch angle on center-side hits.

The Ixx and CG positions of the club head affect the amount of rotation at impact and the gearing effect on a crown-side or sole-side mis-hit, respectively. Therefore, each should be considered when determining the optimal roll radius. The lower the Ixx, the more the club head tends to twist about the X'-axis (1070), which increases the gearing effect on backspin. Additionally, a more rearward CG position increases the rotation about the X'-axis (1070) on a mis-hit when the club head is farther from the geometric center (120). The club head (100) has a roll radius that appropriately considers the Ixx and CG positions. The optimal roll radius balances the launch angle and the gearing effect to provide the right combination of launch angle and backspin rate to maximize the distance of a golf shot.

For example, on a sole-side mis-hit, the gearing effect can increase the backspin of the golf ball, launching the ball higher into the air, causing it to fly higher, but not farther. The roll radius compensates for this increase in backspin by lowering the launch angle on a sole-side mis-hit. In general, a low Ixx increases the gearing effect on a sole-side mis-hit, and a narrow roll radius is needed to more aggressively lower the launch angle. On a crown-side mis-hit, the gearing effect can increase the backspin of the golf ball, hindering the ball's ability to get into the air and stay there, which can decrease distance. The roll radius compensates for this decrease in backspin by increasing the launch angle on a crown-side mis-hit, causing the golf ball's trajectory to fly farther.

Club head COR can also be considered in roll radius optimization for similar reasons as described above. A wider roll radius reduces the oblique impact between the striking face (102) and the golf ball on a crown-side or sole-side mis-hit, thereby maintaining more speed. A high COR club head may have a narrower roll radius to prioritize launch angle and backspin rate, as the high COR naturally maintains speed on mis-hits.

In many embodiments, the roll radius can be determined via computer simulations that take into account a range or values of club head MOI (both Ixx and Iyy) and CG locations. In many embodiments, the computer simulations can be performed for various swing speeds, face transfer angles, and/or impact locations of the striking face (102). In many embodiments, a range of Ixx and a range of Iyy can be selected, and the roll radius can be calculated as a function of the CG location of the club head (100) within the ranges of Ixx and Iyy. In some embodiments, the club head (100) satisfies relationship 2 for Iyy in the range of 2000 g*cm2 to 3200 g*cm2 and Ixx in the range of 1480 g*cm2 to 2370 g*cm2.

For example, in many embodiments, the club head (100) may satisfy relationship 2 and have Iyy of less than 3500 g*㎠, less than 3200 g*㎠, less than 3000 g*㎠, less than 2800 g*㎠, or less than 2600 g*㎠. For example, in many embodiments, the club head (100) may satisfy relationship 2 and have Ixx of less than 2600 g*㎠, less than 2500 g*㎠, less than 2400 g*㎠, less than 2200 g*㎠, less than 2000 g*㎠, less than 1800 g*㎠, or less than 1500 g*㎠.

The bulge radius and the roll radius can be determined independently of each other using the above relationships 1 and 2. However, for a particular club head (100), the bulge and roll radii should be complementary to each other. By further utilizing the above-described computer simulation results, the bulge radius and the roll radius of the club head were determined by considering each other. Accordingly, in some embodiments, the club head (100) satisfies relationships 3 and/or 4 for Iyy in the range of 2000 g*cm2 to 3200 g*cm2 and Ixx in the range of 1480 g*cm2 to 2370 g*cm2.

For example, in many embodiments, the club head (100) can satisfy relationships 3 and 4, and can have an Iyy of less than 3500 g*㎠, less than 3200 g*㎠, less than 3000 g*㎠, less than 2800 g*㎠, less than 2600 g*㎠, less than 2600 g*㎠, less than 2500 g*㎠, less than 2400 g*㎠, less than 2200 g*㎠, less than 2000 g*㎠, less than 1800 g*㎠, or less than 1500 g*㎠, and in many embodiments, the club head (100) having an Iyy of from 2000 g*㎠ to 3200 g*㎠ and an Ixx of from 1480 g*㎠ to 2370 g*㎠ is a club head. Any one or a combination of Relationship 1, Relationship 2, Relationship 3, or Relationship 4 may be satisfied to generate an optimized bulge and roll curvature depending on the characteristics of the head (100).

As previously described, many of the club head embodiments described herein target a low Iyy target. Typically, the bulge and roll curvature optimized for a low-MOI club head can be much narrower than the bulge and roll curvature of a high-MOI club head. In many of the embodiments described herein, the club head (100) can have an Iyy target of 2000 g*cm2 to 3200 g*cm2 and a bulge radius of 5-11 inches. In some embodiments, the club head (100) can have an Iyy target of 2000 g*cm2 to 3200 g*cm2 and a bulge radius of less than 11 inches, less than 10.5 inches, less than 10 inches, less than 9.5 inches, less than 9.0 inches, less than 8.5 inches, less than 8.0 inches, less than 7.5 inches, less than 7.0 inches, less than 6.5 inches, less than 6.0 inches, less than 5.5 inches, or less than 5.0 inches. In some embodiments, the club head (100) can have an Iyy target of 2000 g*cm2 to 3200 g*cm2 and a roll radius of 4-9 inches. In some embodiments, the club head (100) can have an Iyy target of 2000 g*cm2 to 3200 g*cm2 and a roll radius of less than 9.0 inches, less than 8.5 inches, less than 8.0 inches, less than 7.5 inches, less than 7.0 inches, less than 6.5 inches, less than 6.0 inches, less than 5.5 inches, less than 5.0 inches, less than 4.5 inches, or less than 4.0 inches. In many embodiments, the club head (100) has a bulge radius and/or roll radius that is significantly lower than prior art club heads. Traditionally, for prior art driver type club heads, the bulge and roll radius are each about 12 inches, and typically in the range of 10-14 inches.

The optimized bulge and roll curvatures can be applied to a striking face (102) of a club head (100) comprising any one or a combination of the above features. In particular, in many embodiments, the optimized bulge and roll curvatures are applied to a club head (100) having a cubic body shape and a large proportion of the mass distributed near the X'-axis (i.e., a large proportion of the total club head mass distributed within a small center mass region (130). In such embodiments, the club head (100) has a high Ixx/Iyy ratio, which combined with the optimized bulge and roll curvatures provides maximum performance within the context of a particular Iyy target value.

V. Adjustable Swing Weight System

In some embodiments, as referenced in FIGS. 15-22, the club head may include an adjustable swing weight system, which allows for multiple club head configurations of different swing weights, all at a consistent Iyy target. The adjustable swing weight system provides a plurality of replaceable and/or removable weight inserts, each providing a consistent Iyy contribution. "Swing weighting" refers to the process of configuring a club head to a specific total mass to suit the needs of a particular player. For example, some players are suited to a greater total club head mass, while others are better suited to a club head with a lower total mass. Typically, a desired swing weight is achieved by adding one or more replaceable and/or removable weight inserts of varying mass to the club head. However, during this process, the mass characteristics of the club head (including Iyy) will vary from configuration to configuration. The adjustable swing weight system described herein allows for multiple club head configurations of varying mass with little or no change in the club head Iyy. These adjustable swing weight systems can be useful when designers want to achieve a target Iyy for all club head configurations while allowing for a variety of swing weights.

An adjustable swing weight system described herein comprises a plurality of weight inserts, at least one of which is selectable to be coupled to a club head to adjust the swing weight. The plurality of weight inserts can be designed such that, when inserted into a club head, each of the plurality of weight inserts has substantially the same club head Iyy value, yet produces a club head configuration having substantially different club head masses. In particular, the adjustable swing weight system, described in more detail below, allows for a change in club head mass of greater than 26 g, while allowing for a negligible (or no) change in club head Iyy. In some embodiments, the adjustable swing weight system can allow for a club head mass variation between the configurations of greater than 1 g, 2 g, 3 g, 4 g, 5 g, 6 g, 7 g, 8 g, 9 g, 10 g, 11 g, 12 g, 13 g, 14 g, 15 g, 16 g, 17 g, 18 g, 19 g, 20 g, 21 g, 22 g, 23 g, 24 g, or 25 g. In some embodiments, the adjustable swing weight system provides a variation in Iyy between the configurations of less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or about 0%.

To provide a plurality of club head configurations having different swing weights while maintaining a constant Iyy, the adjustable swing weight system described herein includes a plurality of replaceable and/or removable weight inserts of different masses. Each of the plurality of replaceable and/or removable weight inserts can be individually positioned within the club head such that all of the weight inserts have an equal contribution to Iyy. The relationship between the mass, location, and Iyy contribution of the weight inserts is described in detail below.

Given Equation 2 (defined in the Definitions section above), the Iyy contribution of each weight insert can be determined, where the weight insert is treated as a point mass of some mass (m) and offset a vertical distance (r) (also referred to as O _w below) from the Y'-axis (1080). If the Iyy contribution of the weight inserts is constant across configurations, then a consistent Iyy target can be achieved across all available club head configurations. There are two ways to achieve constant Iyy contributions from all weight inserts: 1) the offset of the weight insert CG from the Y'-axis (1080) decreases quadratically as the mass of the weight inserts increases across configurations, or 2) the offset of the weight inserts from the Y'-axis (1080) is negligible or zero (i.e., the weight insert CG is located at the club head CG). In the first method, the mr ² value of the weight insert about the Y'-axis (1080) is kept constant across configurations, while in the second method, the mr ² value is set to zero for all configurations. Various embodiments described in detail below identify club head designs that allow for weight insert configurations with substantially identical Iyy contributions.

FIGS. 15-17c illustrate a two-piece club head (1500) configured to have a tubular recess (1585) for receiving any one of a plurality of weight inserts (1595) of an adjustable swing weight system. The plurality of weight inserts (1595) can include different masses and different weight insert center of gravity (1599) locations to provide consistent Iyy contributions. Referring to FIG. 15 , the club head (1500) can include two bodies, a front portion (1522) and a rear portion (1523). The front portion (1522) and the rear portion (1523) are permanently joined together, such as by welding or adhesive bonding, to form the club head (1500). In some embodiments, the front portion (1522) and the rear portion (1523) can be separate components formed of different materials. In many embodiments, the rear portion (1523) may be a lightweight, non-metallic material, while the front portion (1522) may be metallic. In other embodiments, both the front portion (1522) and the rear portion (1523) may be formed of a metallic material.

The front portion (1522) is configured as a generally hollow concave structure forming an internal cavity (1507) of the club head (1500). The rear portion (1523) may be a generally solid structure having a bore forming a tubular recess (1585). The tubular recess (1585) may extend from the sole (1512) or the rear end (1511) of the club head (1500) into the internal cavity (1507). The tubular recess (1585) is configured to receive a weight insert (1595) corresponding to the club head configuration. The weight insert (1595) is secured in place within the tubular recess (1585) by implementing one or any combination of various retention mechanisms. The retention mechanisms may include a threaded connection, a locking via a post, a securing via a pin, or other non-permanent retention mechanisms known in the art. The tubular recess (1585) is surrounded by a cylindrical shell (1588). The cylindrical shell (1588) is a generally cylindrical barrier that separates the tubular recess (1585) and the interior cavity (1507) of the club head (1500). In some embodiments, once the weight insert (1595) is secured in place within the tubular recess (1585), the cylindrical shell (1588) can be capped to seal the tubular recess (1585). The cylindrical shell (1588) can be permanently or non-permanently sealed using a cap, a plug, or various other methods known in the art. The club head (1500) further includes a support member (1566) that connects the cylindrical shell (1588) to the sole (1512) of the club head (1500). The tubular recess (1585) further includes a tube axis (1586) extending along the length of the tubular recess (1585) through the center of the cylindrical shell (1588), as illustrated in FIG. 15. The tubular recess (1585) is positioned such that the tube axis (1586) aligns with the rifling (1525) of the club head (1500). Aligning the tube axis (1586) with the rifling (1525) of the club head (1500) ensures that launch conditions are consistent between configurations, regardless of which weight insert (1595) the tubular recess (1585) accommodates.

As described above, the weight inserts (1595) are each designed to have a unique weight insert center of gravity (1599) (hereinafter, "CG _WI ") location, and each weight insert (1595) corresponds to a unique club head configuration. Different CG _WI (1599) locations can be provided by varying any combination of the size, shape, or density of each of the plurality of weight inserts (1595). In the illustrated embodiment, each of the plurality of weight inserts (1595) has the same dimensions and is generally cylindrical in shape. However, in other embodiments, the weight inserts (1595) can have different dimensions and can be any shape, including trapezoidal, oval, conical, cubic, or hexagonal. In this embodiment, different CG _WI (1599) locations are provided by varying the density of the weight inserts (1595) along the weight insert length (1596) (hereinafter, "L _WI "). In some embodiments, the weight insert (1595) can be formed of a composite material having a density that varies along the L _WI (1596). Alternative embodiments can vary the CG _WI (1599) location in other ways. For example, in some embodiments, the weight insert (1595) can have a hollow core, and separate weights or multiple weights of varying mass can be positioned along the length of the core to provide specific CG _WI (1599) locations. In some embodiments, the CG _WI (1599) location can be manipulated by forming the weight insert (1595) from multiple materials or composites. In this embodiment, the density of the weight insert (1595) need not vary along the weight insert width (1597) (W _WI ) or the weight insert height (1598) (or H _WI ). As illustrated in FIG. 16, varying the density of the different weight inserts (1595) along each length (L _WI ) allows the CG _WI (1599) to be moved to any position along the length (L _WI ). The unique CG _WI (1599) positions between the weight inserts (1595) allow for a variation of the weight offset (hereinafter “O _w ”) between the configurations. O _w is defined as the distance between the CG (1560) of the club head (1500) and the CG _WI (1599) measured perpendicular to the Y'-axis (1080) and is compatible with ‘r’ in Equation 2. When the weight inserts (1595) are all installed at the same position, for example, in the case of the present embodiment, designing multiple weight inserts (1595) with unique CG _WI (1599) positions allows each weight insert (1595) to have a unique O _w .

FIG. 16 shows a plurality of weight inserts (1592, 1593, 1594), each having a unique CG _WI location. The adjustable swing weight system described herein includes a plurality of cylindrical weight inserts configured according to the embodiment of FIG. 15. Referring to FIG. 16, the plurality of weight inserts (1595) include two or more weight inserts (1595), each having a unique CG _WI (1599) location and a unique mass, as described above. The present embodiment includes a light weight insert (1592), a medium weight insert (1593), and a heavy weight insert (1594). The three weight inserts (1592, 1593, 1594) of the present embodiment are identical in size and shape, but have different masses and CG _WI locations, as described in more detail above. In other embodiments, the plurality of weight inserts (1595) can include any number of weight inserts, including two weight inserts, three weight inserts, four weight inserts, five weight inserts, six weight inserts, seven weight inserts, eight weight inserts, nine weight inserts, ten weight inserts, eleven weight inserts, twelve weight inserts, thirteen weight inserts, fourteen weight inserts, fifteen weight inserts, sixteen weight inserts, seventeen weight inserts, eighteen weight inserts, nineteen weight inserts, or twenty weight inserts.

Figures 17a, 17b and 17c illustrate how each of a plurality of weight inserts (1595) may be accommodated by a club head (1500), each having its own O _w value. The weight inserts (1595) of the present embodiment will be offset by a distance (O _w ) that quadratically increases as the weight insert mass decreases to achieve the same Iyy contribution, such that a lightweight weight insert (1592) as illustrated in Figure 17a will have a larger O _w than a medium weight insert (1593) (illustrated in Figure 17b) or a heavy weight insert (1594) (illustrated in Figure 17c). An offset of the distance (O _w ) of the lightweight weight insert (1592) along the Y'-axis (1080) will produce an Iyy value of the club head (1500) that is greater than that of the club head (1500) when the weight insert (1595) is not accommodated in the tubular recess (1585). The intermediate weight insert (1593) of FIG. 17b will have a smaller O _w than the lightweight weight insert (1592) and an Iyy contribution that is the same as the lightweight weight insert (1592). The identical Iyy contributions of the intermediate weight insert (1593) and the lightweight weight insert (1592) are achieved by providing an O _w for the intermediate weight insert (1593) that decreases quadratically in proportion to the mass increase between the intermediate weight insert (1593) and the lightweight weight insert (1592). Finally, in this example, the heavy weight insert (1594) of FIG. 17c will have a smaller O _w than both the light weight insert (1592) and the medium weight insert (1593). The mass of the heavy weight insert (1594) will also produce the same Iyy contribution as the light weight insert (1592) and the medium weight insert (1593). The same Iyy contribution of the heavy weight insert is achieved by providing an O _w for the heavy weight insert (1594) that decreases quadratically with the increase in mass between the heavy weight insert (1594) and the light weight insert (1592).

The adjustable swing weight system described above allows for variations in the swing weight of the club head while maintaining negligible (or no) variation in the club head Iyy. Additionally, in many embodiments, each weight insert (1595) is at least partially inserted into the club head (1500) such that its CG _WI (1599) location is located along the rifling (1525) of the club head (1500). Providing the CG _WI (1599) along the rifling (1525) ensures consistent launch characteristics across club head configurations since the relative distance between the club head CG (1560) and the rifling (1525) remains constant across configurations.

FIGS. 18-20 illustrate an alternative embodiment of a club head (1600) having an adjustable swing weight system. This embodiment includes all of the same features of the adjustable swing weight system of FIGS. 15-17c, but includes an alternative design for the weight insert (1695). The club head (1600) includes an adjustable swing weight system including a plurality of weight inserts (1695), at least one of the plurality of weight inserts (1695) can be selected to be at least partially inserted into the club head (1600) at different locations to adjust the swing weight of the club head (1600). The embodiments of FIGS. 18-20 utilize the fact that the weight insert (1695) can be treated as a point mass. In particular, since the weight insert (1695) can be treated as a point mass according to Equation 2, the shape and size of the weight insert (1695) need not remain constant. Accordingly, the weight inserts (1695) of the club head (1600) can be cylindrical weights of varying dimensions instead of weight inserts (1695) of the same size and shape. The variation in the dimensions of the weight inserts (1695) for different club head configurations allows for differences in the mass of the weight inserts (1695). To achieve a constant Iyy of the club head (1600) when any one of the plurality of weight inserts (1695) is at least partially inserted into the club head (1600), the weight inserts (1695) are all secured at different individual locations within the tubular recesses (1685) corresponding to different O _w values. Similar to the embodiments illustrated in FIGS. 17a, 17b and 17c, the separate individual locations of the weight inserts (1695) allow for different club head (1600) weights while maintaining substantially the same club head (1600) Iyy value. As described above, consistent Iyy contributions of multiple weight inserts of different masses can be achieved by positioning the weight inserts at or near the club head CG location. Another alternative embodiment of an adjustable swing weight system is illustrated in FIG. 21. This alternative embodiment includes all the same features of the adjustable swing weight system described above and introduces an alternative design for the tubular recess (1785). The tubular recess (1785) is a recess extending from the rear surface (1711) of the club head (1700). The tubular recess (1785) is surrounded by a cylindrical shell (1788). The cylindrical shell (1788) is a generally thin-walled cylindrical barrier that separates the tubular recess (1785) and the internal cavity (1707) of the club head (1700). The club head (1700) further includes a support member (1766) connecting the cylindrical shell (1788) to the sole (1712) of the club head (1700). Any of a plurality of weight inserts (1795) can be inserted into the tubular recess (1785) and configured to be fixed in place when the CG _WI (1799) is aligned with the CG (1760) of the club head (1700). The CG _WI (1799) can be aligned with the CG (1760) of the club head (1700) such that O _W is negligible or zero in all configurations. By aligning the CG _WI (1799) with the CG (1760) of the club head (1700), all of the multiple weight inserts (1795) have zero or negligible contributions to the club head (1700) Iyy, such that substantially the same club head (1700) Iyy can be achieved in all configurations. By providing substantially zero O _W values, the Iyy contribution of the weight inserts (1795) is substantially zero, regardless of the mass of the weight inserts (1795). This embodiment allows for large variations in total club head mass between configurations, while still allowing for negligible variations in Iyy. In this embodiment, the weight inserts (1795) can be composed of various materials, shapes, and/or sizes, as long as each of the multiple weight inserts has a zero or negligible O _W value.

Another embodiment of an adjustable swing weight system is illustrated in FIG. 22. The adjustable swing weight system of FIG. 22 is similar to the embodiment of FIG. 21 except that the tubular recess (1885) extends from the sole (1812) of the club head (1800). In this embodiment, any of a plurality of weight inserts (1895) may be inserted into the tubular recess (1885) and configured such that the CG _WI (1899) aligns with the CG (1860) of the club head (1800). The club head (1800) further includes a support member (1866) that provides support to the base of the cylindrical shell (1888). In many embodiments, the support member (1866) may take the form of a mass pad similar to the sole mass pad described above.

Ⅵ. Additional features

Various embodiments of club heads including the high Ixx/Iyy ratios, optimized bulge and roll curvatures, and/or adjustable swing weight systems described herein may include one or more additional features that provide enhanced performance. The various features described below may be provided in any combination and may be applied to the club heads described in any of the various embodiments described above.

a. Inner rib

In a number of embodiments, such as those illustrated in FIG. 23, the club head (800) may include a plurality of ribs positioned on the inner surface of the body (801) and configured to dampen vibrations and/or structurally reinforce portions of the club head (800). In general, the acoustic and striking feel of a golf club head is highly dependent on the body shape of the club head. The cubic body shape of the club head described herein may, in some cases, introduce a dominant vibration upon impact, resulting in a harsh sound or feel upon impact. The ribs are provided to dampen the dominant vibration, thereby providing a more desirable and muted sound and striking feel.

In various embodiments, the club head (800) may include any number of ribs, one or more of which may extend along an interior surface of the sole (812), the crown (810), the skirt (814), or any combination thereof. In the exemplary embodiment of FIG. 23, the club head (800) includes a pair of center ribs (835) extending across a substantial portion of the sole interior surface (821). The center ribs (835) each extend obliquely across the sole interior surface (821) from substantially near the heel (804) to substantially near the toe (806). In many embodiments, the center ribs (835) may be substantially parallel to one another. The center ribs provide a damping effect across a substantial portion of the sole (812), which is the general region where dominant vibrations occur. The club head (800) further includes a pair of rear ribs (836) located near the rear end (811) and extending substantially in a fore-aft and aft direction. The rear rib (836) may be particularly useful in embodiments that include a weight member (as described above) coupled to the lower rear portion of the body (801). In such embodiments, the rear rib (836) is effective in damping vibrations that occur by providing a weight member to the rear portion of the club head (800). The club head (800) of the illustrated embodiment further includes a sole mass pad (840) as described in detail above. One or more of the center rib (835) and/or the rear rib (836) may contact or intersect the sole mass pad (840).

Vibration control in golf club head design relies heavily on localized reinforcement of high-vibration areas. Accordingly, any of the center ribs (835) and/or the rear ribs (836) may be provided in any location or orientation, such as a heel-toe orientation, a fore-aft orientation, a diagonal orientation, or any combination thereof. As described above, the ribs provide vibration control to compensate for any dominant vibrations associated with the unique body shape and mass distribution of the club head described herein. The ribs allow for a club head that achieves a high Ixx/Iyy ratio while providing desirable acoustics and feel.

b. Aerodynamic features

As previously described, the club head may include several features to maximize aerodynamic characteristics while still balancing the Ixx/Iyy ratio. Specifically, the club head may include at least a turbulator, a sole transition profile, a crown transition profile, a back transition profile, and a back cavity. In general, the aerodynamic drag of a golf club head is determined by the body shape (i.e., pressure drag/form drag) that causes flow separation. Compared to modern "flat" clubs, the club head of the present invention may generate less drag during a swing due to its smaller surface area or volume, which may be introduced to achieve a target Iyy value. Compared to older, prior art club heads, the club head of the present invention may generate less drag during a swing due to its integrated aerodynamic features.

In some embodiments, the club head can include a plurality of turbulators as described in U.S. Patent No. 8,608,587, issued December 17, 2013, and U.S. Patent Application No. 13/536,753, filed June 28, 2021, entitled "Golf Club Head Having Turbulators and Method of Making Golf Club Head Having Turbulators," which is fully incorporated herein by reference. Turbulators on the crown are known in the art to reduce drag. Turbulators disrupt airflow to activate flow and delay flow separation. Thus, the turbulators reduce drag generated by the club head during a swing and increase speed.

The club head may further include a crown transition profile, a sole transition profile, and/or a back transition profile, which are similar to the crown transition profile, sole transition profile, and back transition profile described in U.S. Patent Application No. 15/233,486, filed Aug. 10, 2016, and issued July 31, 2018, entitled “Golf Club Head Having Transition Profile for Reducing Aerodynamic Drag,” which is incorporated herein by reference. The club head can include a front crown radius of curvature, a sole radius of curvature, and/or a back radius of curvature, which can be similar to the first crown radius of curvature, the first sole radius of curvature, and/or the back radius of curvature described in U.S. Patent Application No. 15/233,486, filed Aug. 10, 2016, and issued July 31, 2018, entitled “Golf Club Head Having Transition Profile for Reducing Aerodynamic Drag.”

The front curvature radius can be 0.18-0.30 inches (0.46-0.76 cm). Additionally, in other embodiments, the front curvature radius (392) can be less than 0.40 inches (1.02 cm), less than 0.375 inches (0.95 cm), less than 0.35 inches (0.89 cm), less than 0.325 inches (0.83 cm), or less than 0.30 inches (0.76 cm).

The sole radius of curvature can range from about 0.25 to 0.50 inches (0.76 to 1.27 cm). In some embodiments, the sole radius of curvature can be less than 0.5 inches (1.27 cm), less than 0.475 inches (1.21 cm), less than 0.45 inches (1.14 cm), or less than 0.40 inches (1.02 cm).

The rear curvature radius can range from 0.10 to 0.25 inches (0.25 to 0.64 cm). In some embodiments, the rear curvature radius can be less than 0.3 inches (0.76 cm), less than 0.275 inches (0.70 cm), less than 0.25 inches (0.64 cm), less than 0.225 inches (0.57 cm), or less than 0.20 inches (0.51 cm).

Additionally, the club head may further include a cavity located at the rear end and rear edge of the club head, which cavity is similar to the cavity described in U.S. Patent No. 9,492,721, issued Nov. 15, 2016, entitled “Golf Club Head Having Aerodynamic Features and Related Methods,” which is fully incorporated herein by reference. In many embodiments, the cavity (420) may break up the vortex generated behind the golf club head (300) into smaller vortices to reduce the size of the wake and/or reduce drag.

yes

Ⅶ. Example 1: 3700 g*㎠ Iyy target value

A first exemplary club head is designed to maximize performance in the context of an Iyy target. The first exemplary club head has a cube-shaped body shape and a significant portion of the club head mass distributed near the Y'-axis. The first exemplary club head is designed for an Iyy target of 3700 g*cm2. The first exemplary club head has a body width (W _B ) of 4.4 inches, a body height (H _B ) of 2.31 inches, a body depth (D _B ) of 4.31 inches, and a volume of 446 cm3. These body dimensions result in an H _B /W _B ratio of 0.53 and an H _B /D _B ratio of 0.54. The club head additionally includes a mass pad covering a significant portion of the interior surface of the sole. The mass pad has a mass of 24 g and is positioned centrally on the sole so as to intersect the Y'-axis. Additionally, 11.2% of the total mass of the exemplary club head is located within a center mass area having a radius of 0.75 inches (R _CMZ ). The exemplary club head additionally has a removable weight member that is bonded to the body in a very low rearward position between the rear end and the sole, with a mass of 32 grams. The club head additionally includes a multi-material body structure with a significant portion of the crown and various portions of the heel, toe, and sole constructed of non-metallic materials.

The body shape, mass distribution, weight member arrangement, and multi-material structure of the first exemplary club head resulted in an Ixx of 3051 g*cm2 and an Iyy of 3650 g*cm2. Therefore, the first exemplary club head has an Ixx/Iyy ratio of 0.84.

Ⅷ. Example 2: 2600 g*cm2 Iyy target by crown and sole mass pad

A second exemplary club head is designed to maximize performance in the context of an Iyy target. The second exemplary club head has a cube-shaped body shape and a significant portion of the club head mass distributed near the Y'-axis. The second exemplary club head is designed to have an Iyy target of 2600 g*cm2. The second exemplary club head has a body width (W _B ) of 3.95 inches, a body height (H _B ) of 2.44 inches, a body depth (D _B ) of 3.85 inches, and a volume of 332 cm3. These body dimensions result in an H _B /W _B ratio of 0.62 and an H _B /D _B ratio of 0.63. The second exemplary club head further includes a first mass pad positioned on an inner surface of the sole. The first mass pad is positioned centrally in the sole and intersects the Y'-axis and the YZ plane. The first mass pad is spaced more than 10% of the body depth aft of the leading edge. The first mass pad is completely contained within a center mass area having a radius (R _CMZ ) of 0.75 inches. The club head further includes a second mass pad positioned on an inner surface of the crown. The second mass pad is positioned at a central portion of the crown and intersects the Y'-axis and the YZ plane. The second mass pad is spaced more than 10% of the body depth aft of the leading edge. The second mass pad is also completely contained within the same center mass area. The first mass pad and the second mass pad have a total mass of 22.3 g. The club head further includes a third mass pad positioned on an inner surface aft of the first mass pad. The third mass pad covers a majority of the sole inner surface between the first mass pad and the rear end of the club and has a mass of 46 g. Additionally, 21% of the total mass of the exemplary club head is located within the center mass area. The second exemplary club head includes a single material body structure that is free of any additional weight elements and free of any non-metallic components.

The body shape, mass pad arrangement, and mass distribution of the second exemplary club head result in an Ixx of 2077 g*cm2 and an Iyy of 2568 g*cm2. Therefore, the second exemplary club head has an Ixx/Iyy ratio of 0.81. Unlike exemplary club head 1, exemplary club head 2 can achieve the Ixx/Iyy ratio without using any additional weights attached to the body. Exemplary club head 2 provides a high Ixx/Iyy ratio through the centrally located mass pad and higher H _B /W _B and H _B /D _B ratios.

Ⅸ. Example 3: 2600 g*㎠ Iyy target by rear weight

A third exemplary club head is designed to maximize performance in the context of an Iyy target. The third exemplary club head has a cube-shaped body shape and a significant portion of the club head mass distributed near the Y'-axis. The third exemplary club head is designed to have an Iyy target of 2600 g*cm2. The third exemplary club head has a body width (W _B ) of 3.6 inches, a body height (H _B ) of 2.4 inches, a body depth (D _B ) of 3.5 inches, and a volume of 280 cm3. These body dimensions result in a H _B /W _B ratio of 0.67 and a H _B /D _B ratio of 0.69. The third exemplary club head further includes a first mass pad positioned on an interior surface of the sole proximate the rear end. The first mass pad covers a majority of the rear half of the interior surface of the sole and is spaced from the leading edge by more than 40% of the body depth. The first mass pad is provided at a sole-side extreme location. The first mass pad has a mass of 33 g. The club head further includes a second mass pad positioned on an inner surface of the crown. The second mass pad is positioned in a central portion of the crown such that the Y'-axis intersects the YZ plane. The second mass pad is spaced more than 10% of the body depth aft of the leading edge. The second mass pad is entirely contained within a center mass area having a radius (R _CMZ ) of 0.75 inches. Additionally, 20.8% of the total mass of the exemplary club head is located within the center mass area. The third exemplary club head further includes a weight member coupled to the rear end of the club head at a very low rearward position and having a mass of 30 g. The third exemplary club head includes a single material body structure free of any non-metallic components.

The body shape, mass pad arrangement, mass distribution, and absence of weights of the third exemplary club head result in an Ixx of 2258 g*cm2 and an Iyy of 2475 g*cm2. Therefore, the second exemplary club head has an Ixx/Iyy ratio of 0.88. The third exemplary club head achieves the higher Ixx/Iyy ratio compared to exemplary club heads 1 and 2 by providing a combination of very high H _B /W _B and H _B /D _B ratios, a very low-positioned mass pad on the inner sole surface, a second mass pad positioned centrally in the crown, and a very low, rearward weight positioned rearward.

X. Example 4: 2700 g*㎠ Iyy target by rear weight, crown and sole mass pad

A fourth exemplary club head is designed to maximize performance in the context of an Iyy target. The fourth exemplary club head has a cube-shaped body shape and a significant portion of the club head mass distributed near the Y'-axis. The fourth exemplary club head is designed to have an Iyy target of 2700 g*cm2. The fourth exemplary club head has a body width (W _B ) of 3.96 inches, a body height (H _B ) of 2.23 inches, a body depth (D _B ) of 3.74 inches, and a volume of 291 cm3. These body dimensions result in an H _B /W _B ratio of 0.56 and an H _B /D _B ratio of 0.69. The fourth exemplary club head further includes a first mass pad located on an inner surface of the sole, the first mass pad weighing 50 g, the first mass pad located in a central portion of the sole and intersecting the Y'-axis and the YZ plane. A first mass pad is spaced more than 10% of the body depth aft of the leading edge. The first mass pad is positioned entirely within a first center mass area having a radius (R _CMZ1 ) of 0.825 inches. The club head further includes a second mass pad positioned on an inner surface of the crown, wherein the second mass pad is about 6 grams. The second mass pad is positioned at a central portion of the crown and intersects the Y'-axis and the YZ plane. The second mass pad is spaced more than 10% of the body depth aft of the leading edge. The second mass pad is positioned entirely within a second center mass area having a second radius (R _CMZ2 ) of 0.50 inches. Additionally, 25% of the total mass of the exemplary club head is positioned within a third center mass area having a third radius (R _CMZ3 ) of 0.75 inches. A fourth exemplary club head has an additional weight member having a mass of 16 g and is coupled to the rear end of the club head in a very low rearward position. The fourth exemplary club head includes a single material body structure without any non-metallic components.

The body shape, mass pad arrangement, mass distribution, and absence of weights of the fourth exemplary club head result in an Ixx of 2161 g*cm2 and an Iyy of 2679 g*cm2. Therefore, the second exemplary club head has an Ixx/Iyy ratio of 0.80. The fourth exemplary club head has a high Ixx/Iyy ratio due to a large proportion of the mass being located within the central mass area provided by the centrally located first and second mass pads. However, compared to exemplary club heads 1-3, exemplary club head 4 exhibits a somewhat lower Ixx/Iyy ratio due to its relatively low H _B /W _B ratio.

XI. Example 5: Comparison of Ixx/Iyy ratios

The club head body dimensions (body height (H _B ), body width (W _B ), and body depth (D _B ) and moments of inertia) of the first, second, third, and fourth exemplary clubs described above are compared to a plurality of prior art control club heads. The control club heads are designed to maximize Iyy rather than to maximize the Ixx/Iyy ratio. Control club head 1 represents a "modern" prior art club head having a generally flat club head shape. Control club head 1 is designed to maximize Iyy through a multi-material body structure comprising a significant portion of the crown made of non-metallic materials and high perimeter weighting. Control club head 2, control club head 3, and control club head 4 represent existing prior art club heads which tend to have a more spherical club head shape, but without specific weight structures, weight members, or mass distributions designed to increase the Ixx/Iyy ratio. The dimensions of each club head are set forth in Table 1 below.

Table 1

As can be seen in Table 1 above, the exemplary club heads exhibit increased Ixx/Iyy ratios compared to both the flatter, more modern control club head 1 and the older, more traditional control club heads 2-4. For the control club head 1, the increased Ixx/Iyy ratios exhibited by the exemplary club head are due to the club head geometry. The exemplary club head has a much more cubic body geometry than the control club head 1. The exemplary club heads exhibited increases in the H _B /W _B ratios of 10-40% and increases in the H _B /D _B ratios of 10-41% compared to the control club head 1. The increased H _B /W _B and H _B /D _B ratios resulted in an Ixx/Iyy ratio that was 4-14% higher than the control club head 1.

For the control club heads 2-4, the exemplary club heads exhibited Ixx/Iyy ratios that were increased by 33-49%. The control club heads 2-4 exhibited H _B /W _B and H _B /D _B ratios greater than 0.50, but did not have the weight features or mass distribution near the Y'-axis described above with respect to the exemplary club heads. Despite the spherical shape of the control club heads 2-4, the absence of any mass pad, weight member, or mass placement near the Y'-axis resulted in significantly lower Ixx values. This example demonstrates that a combination of a cubic body shape and the placement of any discretionary mass near the Y'-axis can achieve high Ixx/Iyy ratios.

XⅡ. Example 6: Offline distance vs. optimal bulge radius deviation (Iyy target: 2000 g*㎠)

The example illustrates the importance of providing an optimal bulge radius for a given club head as described in the above embodiments. Referring to FIG. 25, an exemplary golf club head is configured with a target Iyy of 2000 g*cm2, and additionally has an Ixx of 1480 g*cm2 and a COR of 0.785. According to Relationships 1-4 detailed above, the club head includes a striking face having optimal bulge and roll curvatures. The optimal bulge radius is provided as 6.77 inches, and the optimal roll radius is provided as 4.59 inches. FIG. 25 shows the percentage increase in the off-line distance standard deviation resulting from deviations from the optimal bulge radius of the exemplary club head ("% Change Bulge Radius"). The graph shows the detrimental effects of providing a non-optimal bulge radius to the exemplary club head. As illustrated in FIG. 25, as the bulge radius deviates from the optimal value, the accuracy of the club head decreases significantly (i.e., the off-line distance from the target line increases).

As exemplified by points (2010 and 2020), even a small deviation from the optimal bulge radius can result in a significant loss of accuracy. Point (2010) exhibits a bulge radius that is 2 inches (29.5%) less than the optimal bulge radius, which results in an off-line distance standard deviation increase of 54.3%. Point (2020) exhibits a bulge radius that is 2 inches (29.5%) greater than the optimal bulge radius, which results in an off-line distance standard deviation increase of 54.3%. These examples demonstrate that even a small deviation from the optimal bulge radius (i.e., as little as 2 inches) is detrimental to accuracy. Therefore, providing an optimized bulge radius for a particular club head according to the present invention is important to maximizing club head forgiveness. This is especially true for club heads targeting a low Iyy, since the optimized bulge and roll curvature compensates for any forgiveness lost by providing a low Iyy.

XⅢ. Example 7: Offline distance vs. optimal bulge radius deviation (Iyy target: 3200 g*㎠)

This example further illustrates the importance of providing an optimal bulge radius for a given club head as described in the embodiments above. Referring to FIG. 26, an exemplary golf club head is configured with a target Iyy of 3200 g*cm2, and additionally has an Ixx of 2368 g*cm2 and a COR of 0.814. According to Relationships 1-4 detailed above, the club head includes a striking face having optimal bulge and roll curvatures. The optimal bulge radius is provided as 9.34 inches, and the optimal roll radius is provided as 6.31 inches. FIG. 26 shows the percentage increase in the off-line distance standard deviation resulting from the deviation of the exemplary club head from the optimal bulge radius ("% Change Bulge Radius"). The graph shows the detrimental effects of providing a non-optimal bulge radius for the exemplary club head. As illustrated in FIG. 26, as the bulge radius deviates from the optimal value, the accuracy of the club head decreases significantly (i.e., the off-line distance from the target line increases).

As exemplified by points (3010 and 3020), even a small deviation from the optimal bulge radius can result in a significant loss of accuracy. Point (3010) exhibits a bulge radius that is 2 inches (21.4%) less than the optimal bulge radius, which results in an off-line distance standard deviation increase of 12.97%. Point (3020) exhibits a bulge radius that is 2 inches (21.4%) greater than the optimal bulge radius, which results in an off-line distance standard deviation increase of 4.32%. These examples demonstrate that even a small deviation from the optimal bulge radius (i.e., as little as 2 inches) is detrimental to accuracy. Therefore, providing an optimized bulge radius for a particular club head according to the present invention is important to maximizing club head forgiveness.

XⅣ. Example 8: Standard Bulge and Roll Radius vs. Optimized Bulge and Roll Radius

A plurality of exemplary club heads including striking faces having optimized bulge and roll curvatures according to the present invention were compared to a plurality of corresponding control club heads having standard bulge and roll curvatures that are not optimized for a particular characteristic of the club head. Each exemplary club head corresponds to a control club head having the same characteristics but with different bulge and roll curvatures. Each control club head has a bulge radius of 12 inches and a roll radius of 12 inches, which are typical prior art curvatures for driver-type club heads. The optimized bulge and roll radii of the exemplary club heads fall within the ranges specified above and are significantly smaller than the standard bulge and roll radii of the control club heads. Table 2 below compares the average distances and off-line distance standard deviations for a plurality of exemplary club heads and control club head pairings, each having a different combination of Iyy target and COR.

Table 2

As shown (above), the exemplary club head significantly increases both distance and off-line distance compared to the control club head. The exemplary club head exhibited distance increases from 3.25 yards (1.2% increase) to 11.56 yards (4.3% increase) compared to the control club head. Additionally, the exemplary club head exhibited a significant reduction in the standard deviation of off-line distance from 2.76 yards (17% decrease) to 10.86 yards (45% decrease). As a result, it was found that applying the industry standard bulge and roll radius (12 inches) failed to maximize both distance and off-line accuracy. In contrast, the exemplary club head with optimized bulge and roll curvatures significantly improved both distance and accuracy.

The optimization of the bulge and roll radius according to the present invention and the relationships discussed above provide golf club heads that hit the ball farther and are much more forgiving. Additionally, while all of the exemplary club heads showed improvements over the control club heads, the improvements tended to be more pronounced for the low-MOI club heads, regardless of the Iyy target. As a result, the bulge and roll radius of the present invention demonstrates that it provides performance improvements for any MOI. Nevertheless, the optimized bulge and roll radius of the present invention is uniquely advantageous for low-MOI club heads. Optimization of the bulge and roll radius can compensate for the natural loss of forgiveness associated with low-MOI club heads.

XV. Example 9: High-MOI Clubhead vs. Low-MOI Clubhead with Bulge Radius and Roll Radius Derived from CG Location

An exemplary club head having a striking face with a low-MOI target and optimized bulge and roll radius was compared to a prior art high-MOI club head (hereinafter, the "control club head") having standard bulge and roll radius that is not optimized for a particular characteristic of the club head. The exemplary golf club head has a target Iyy of 2600 g*cm2, an Ixx of 1924 g*cm2, and a COR of 0.785. The control golf club head has an Iyy of 5700 g*cm2, an Ixx of 4218 g*cm2, and a COR of 0.83. The control club head has an additional bulge and roll radius of approximately 12 inches each. Table 3 below compares the average distances and off-line distance standard deviations of the control club heads and the exemplary club heads.

Table 3

As illustrated in Table 3, the exemplary club head exhibited a decrease in distance. However, the decrease in distance may be attributed to the difference in COR rather than the bulge and roll curvatures. Despite the very low moment of inertia, the exemplary club head exhibited an improvement in accuracy compared to the high-MOI golf club head. Although the exemplary club head had a 54% reduction in Iyy, the exemplary club head exhibited a 10.9% reduction in the off-line distance standard deviation. As a result, it is shown that the optimized bulge and roll curvatures can overcome the defect caused by reducing the club head moment of inertia and provide improved accuracy compared to the high-MOI club head.

XⅥ. Example 10: Clubhead with adjustable swing weight and constant Iyy

An exemplary club head is designed with an adjustable swing weight system to allow the club head to have a total club head mass change of 26 g and a variation in club head Iyy of less than 0.1 g*cm2. The exemplary club head including the adjustable swing weight system is substantially similar to the embodiments illustrated in FIGS. 18-20. The adjustable swing weight system of the exemplary club head includes a plurality of replaceable and/or removable weight inserts including a lightweight weight insert, a mid-weight insert, and a heavy weight insert. Each of the plurality of weight inserts corresponds to an exemplary club head configuration including a lightweight club head configuration (associated with the lightweight weight insert), a mid-club head configuration (associated with the mid-weight insert), and a heavy club head configuration (associated with the heavy weight insert). Each of the plurality of weight inserts is associated with a unique individual location and weight insert offset (O _W ) value within the tubular recess.

The tubular recess of the exemplary club head has a length of 2.25 inches. The lightweight weight insert is positioned toward the rear of the tubular recess to provide an offset value (O _W ) of 2.20 inches from the club head center of gravity along the ridge. The mid-weight insert is positioned closer to the center of the tubular recess and has an offset value (O _W ) of 1.63 inches. The heavy weight insert is positioned farthest forward of the tubular recess and the heavy weight insert and has an offset value (O _W ) of 1.38 inches. The lightweight weight insert of the exemplary club head has a mass of 14.87 g, the mid-weight insert has a mass of 27.87 g, and the heavy weight insert has a mass of 40.87 g. The mass of the club head without the weight inserts is maintained at a constant value of 175.20 g. Since the replaceable and/or removable weight inserts are configured within the same club head body, any variation in club head Iyy will inevitably result from variations in the weight inserts and their locations. The different masses of the weight inserts are varied by providing different shapes and densities for each weight insert. The density of the lightweight weight insert was 9.44 g/cm3, the density of the medium weight insert was 12.59 g/cm3, and the density of the heavy weight insert was 17.31 g/cm3. Selected values for club head mass, weight insert mass, weight insert offset, and the resulting Iyy values for each configuration are summarized in Table 4 below. This example demonstrates the ability of the adjustable swing weight system to provide consistent Iyy between configurations to meet a desired Iyy target. Therefore, no Ixx values are reported in Table 4.

Table 4

As shown in Table 4, the exemplary adjustable swing weight system allows the total club head mass to be changed by as much as 26 g while keeping the club head Iyy constant.

The configurations presented in Table 4 for the lightweight club head configuration, mid-club head configuration, and heavy club head configuration were determined based on an Iyy target of 2667 g*cm2, a minimum desired club head configuration mass of 190 g, and a maximum desired club head configuration mass of 216 g. The selected Iyy target values, number of weight inserts, and desired swing weights are for illustration purposes only and do not represent limitations of the adjustable swing weight system described herein. For example, if it is determined desirable to achieve a larger Iyy target value in terms of total club head mass, the tubular recess length of the club head can be designed to be larger to position the weights farther from the club head CG and achieve a larger Iyy value. Similarly, if it is determined desirable to achieve a greater variation in swing weight across the various club head configurations, multiple weight inserts having a greater variation in mass can be selected and positioned accordingly.

port

Article 1. A golf club head, comprising: a striking face including a geometric center, a leading edge, a body, a center of gravity, a ground plane and a total club head mass, the body including a crown, a sole, a heel, a toe and a rear end; a primary coordinate system centered around the geometric center, the coordinate system defining: an X-axis extending in a heel-toe direction parallel to the ground plane; a Y-axis extending in a crown-sole direction perpendicular to the X-axis and the ground plane; a Z-axis extending in a striking face-rear direction perpendicular to the X-axis and the Y-axis; an auxiliary coordinate system centered around the center of gravity, the auxiliary coordinate systems defining: an X'-axis extending in a heel-toe direction parallel to the ground plane; a Y'-axis extending in a crown-sole direction perpendicular to the X'-axis and the ground plane; defining a Z'-axis extending in the striking face-rear direction orthogonal to both the X'-axis and the Y'-axis; wherein the body has a body width measured parallel to the X-axis between the heel and the toe; a body depth measured parallel to the Z-axis between the leading edge and a rearmost point of the body; a body height measured parallel to the Y-axis between the ground plane and a highest point of the crown; wherein the club head has a H _B /W _B ratio defined as the body height divided by the body width, wherein the H _B /W _B ratio is greater than 0.6; a moment of inertia (Ixx) about the X'-axis; a moment of inertia (Iyy) about the Y'-axis; and a moment of inertia (Izz) about the Z'-axis, wherein the club head has an Ixx/Iyy ratio greater than 0.8; A golf club head comprising a center mass area defined by an imaginary cylinder centered about the Y'-axis, the center mass area defining a center mass area radius of 0.75 inches, and wherein more than 20% of the total club head mass is located within the center mass area.

Clause 2. A golf club head according to Clause 1, further comprising a crown mass pad positioned on an inner surface of the crown and a sole mass pad positioned on an inner surface of the sole, wherein the crown mass pad and the sole mass pad each intersect the Y'-axis.

Clause 3. A golf club head according to clause 2, wherein at least one of the crown mass pad and the sole mass pad is completely defined within the center mass area.

Clause 4. A golf club head according to clause 2, wherein the sole mass pad has a mass greater than 5 g.

Clause 5. A golf club head according to clause 2, wherein the crown mass pad has a mass greater than 25 g.

Clause 6. A golf club head according to clause 1, wherein the body width is less than 4.0 inches.

Article 7. A golf club head according to Article 1, wherein the body height is greater than 2.2 inches.

Article 8. A golf club head according to Article 1, wherein the club head has a volume of less than 350 cm3.

Article 9. A golf club head according to Article 1, wherein the Ixx/Iyy ratio is greater than 0.85.

Clause 10. A golf club head according to clause 1, further comprising: a YZ plane extending along the Y-axis and the Z-axis; a crown transition point located at a forward-most point of the crown within the YZ plane; a rearward transition point located at a rearward-most point of the crown within the YZ plane; a crown axis extending between the crown transition point and the rearward transition point; and a crown angle measured as an acute angle between the crown axis and the Y'-axis, the crown angle being greater than 75 degrees.

Item 11. A golf club head according to Item 10, wherein the crown angle is greater than 85 degrees.

Clause 12. A golf club head according to clause 1, further comprising a weight member attached to the body proximate the rear end and the sole; wherein the weight member defines a weight member center of gravity; wherein the weight member has a weight member height defined as a distance between the center of gravity of the club head and the center of gravity of the weight member, measured parallel to the Y'-axis; wherein the weight member further has a weight member depth defined as a distance between the center of gravity of the club head and the center of gravity of the weight member, measured parallel to the Y'-axis; wherein the club head defines an E _W /D _W ratio defined as the weight member height divided by the weight member depth; wherein the E _W /D _W ratio is greater than 0.3.

Article 13. A golf club head, comprising: a striking face including a geometric center, a leading edge, a body, a center of gravity, a ground plane and a total club head mass, the body including a crown, a sole, a heel, a toe and a rear end; a primary coordinate system centered around the geometric center, the coordinate system defining: an X-axis extending in a heel-toe direction parallel to the ground plane; a Y-axis extending in a crown-sole direction perpendicular to the X-axis and the ground plane; a Z-axis extending in a striking face-rear direction perpendicular to the X-axis and the Y-axis; an auxiliary coordinate system centered around the center of gravity, the auxiliary coordinate systems defining: an X'-axis extending in a heel-toe direction parallel to the ground plane; a Y'-axis extending in a crown-sole direction perpendicular to the X'-axis and the ground plane; defining a Z'-axis extending in the striking face-rear direction orthogonal to both the X'-axis and the Y'-axis; wherein the body has a body width measured parallel to the X-axis between the heel and the toe; a body depth measured parallel to the Z-axis between the leading edge and a rearmost point of the body; a body height measured parallel to the Y-axis between the ground plane and a highest point of the crown; wherein the club head has a H _B /W _B ratio defined as the body height divided by the body width, wherein the H _B /W _B ratio is greater than 0.6; a moment of inertia (Ixx) about the X'-axis; a moment of inertia (Iyy) about the Y'-axis; and a moment of inertia (Izz) about the Z'-axis, wherein the club head has an Ixx/Iyy ratio greater than 0.8; A center mass area defined by an imaginary cylinder centered about the Y'-axis, said center mass area defining a center mass area radius of 0.75 inches; wherein said club head defines a mass distribution index (MD ₁ ) according to Equation 1:

(1)

- M _CMZ is the mass within the center mass region, M _T is the total club head mass, and R _CMZ is the center mass region radius -; A golf club head wherein the mass distribution index (MD ₁ ) is greater than 0.1.

Item 14. A golf club head according to Item 13, further comprising a crown mass pad positioned on an inner surface of the crown and a sole mass pad positioned on an inner surface of the sole, wherein the crown mass pad and the sole mass pad each intersect the Y'-axis.

Clause 15. A golf club head according to clause 14, wherein at least one of the crown mass pad and the sole mass pad is completely defined within the center mass area.

Article 16. A golf club head, comprising: a striking face including a geometric center, a leading edge, a body, a center of gravity, a ground plane and a total club head mass, the body including a crown, a sole, a heel, a toe and a rear end; a primary coordinate system centered around the geometric center, the coordinate system defining: an X-axis extending in a heel-toe direction parallel to the ground plane; a Y-axis extending in a crown-sole direction perpendicular to the X-axis and the ground plane; a Z-axis extending in a striking face-rear direction perpendicular to the X-axis and the Y-axis; an auxiliary coordinate system centered around the center of gravity, the auxiliary coordinate systems defining: an X'-axis extending in a heel-toe direction parallel to the ground plane; a Y'-axis extending in a crown-sole direction perpendicular to the X'-axis and the ground plane; defining a Z'-axis extending in the striking face-rear direction orthogonal to both the X'-axis and the Y'-axis; wherein the body has a body width measured parallel to the X-axis between the heel and the toe; a body depth measured parallel to the Z-axis between the leading edge and a rearmost point of the body; a body height measured parallel to the Y-axis between the ground plane and a highest point of the crown; wherein the club head has a H _B /W _B ratio defined as the body height divided by the body width, wherein the H _B /W _B ratio is greater than 0.6; a moment of inertia (Ixx) about the X'-axis; a moment of inertia (Iyy) about the Y'-axis; and a moment of inertia (Izz) about the Z'-axis, wherein the club head has an Ixx/Iyy ratio greater than 0.8; A center mass area defined by an imaginary cylinder centered about the Y'-axis, said center mass area defining a center mass area radius of 0.75 inches; wherein said club head defines a mass distribution index (MD ₃ ) according to Equation 1:

(1)

- M _CMZ is the mass within the center mass region, and M _T is the total club head mass; -; A golf club head, wherein the mass distribution index (MD ₃ ) is greater than 0.005.

Item 17. A golf club head according to Item 16, further comprising a crown mass pad positioned on an inner surface of the crown and a sole mass pad positioned on an inner surface of the sole, wherein the crown mass pad and the sole mass pad each intersect the Y'-axis.

Clause 18. A golf club head according to clause 17, wherein at least one of the crown mass pad and the sole mass pad is completely defined within the center mass area.

Clause 19. A golf club head according to clause 16, wherein Iyy is less than 3200 g*㎠.

Clause 20. A golf club head according to clause 16, wherein Iyy is less than 2800 g*㎠.

Clause 21. In clause 16, the striking surface further has a bulge curvature and a roll curvature, and the bulge curvature has a bulge radius satisfying relation 1;

A golf club head, wherein CGy is the position of the center of gravity with respect to the Y-axis, and CGz is the position of the center of gravity with respect to the Z-axis.

Clause 22. A golf club head according to clause 16, wherein the club head comprises a plurality of interchangeable weight inserts; each of the plurality of interchangeable weight inserts is associated with a different club head configuration; each of the club head configurations is associated with a different total club head mass; and Iyy is constant between each of the club head configurations.

Claims (22)

As a golf club head:
A striking face including a geometric center and a leading edge, a body, a center of gravity, a ground plane and total club head mass; - said body including a crown, sole, heel, toe and rear end -;
A basic coordinate system centered around the geometric center, - said basic coordinate system being:
X-axis extending in the heel-toe direction parallel to the above ground plane;
A Y-axis extending in the crown-sole direction orthogonal to the above X-axis and the above ground plane;
- A Z-axis is defined extending in the direction of the striking surface-rear surface so as to be orthogonal to both the X-axis and the Y-axis;
An auxiliary coordinate system centered on the above center of gravity, - said auxiliary coordinate system being:
X'-axis extending in the heel-toe direction parallel to the above ground plane;
A Y'-axis extending in the crown-sole direction so as to be orthogonal to the above X'-axis and the above ground plane;
- A Z'-axis is defined extending in the direction of the rear surface of the striking surface so as to be orthogonal to both the X'-axis and the Y'-axis;
Including,
The above body:
Body width measured parallel to the X-axis between the heel and the toe;
Body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body;
having a body height measured parallel to the Y-axis between the ground plane and the highest point of the crown;
The above club head,
The H _B /W _B ratio defined as the body height divided by the body width, wherein the H _B /W _B ratio is greater than 0.6;
Moment of inertia about the X'-axis (Ixx);
Moment of inertia about the Y'-axis (Iyy);
Moment of inertia about the Z'-axis (Izz);
Ixx/Iyy ratio greater than 0.8;
A golf club head comprising a center mass area defined by an imaginary cylinder centered about the Y'-axis, the center mass area defining a center mass area radius of 0.75 inches, and wherein more than 20% of the total club head mass is located within the center mass area. In the first paragraph, a crown mass pad positioned on the inner surface of the crown and a sole mass pad positioned on the inner surface of the sole are further included;
A golf club head wherein the crown mass pad and the sole mass pad each intersect the Y'-axis. A golf club head in claim 2, wherein at least one of the crown mass pad and the sole mass pad is defined entirely within the center mass area. A golf club head in claim 2, wherein the sole mass pad has a mass greater than 5 g. A golf club head in claim 2, wherein the crown mass pad has a mass greater than 25 g. A golf club head in claim 1, wherein the body width is less than 4.0 inches. A golf club head in claim 1, wherein the body height is greater than 2.2 inches. A golf club head in claim 1, wherein the club head has a volume of less than 350 cm3. A golf club head in claim 1, wherein the Ixx/Iyy ratio is greater than 0.85. In the first paragraph,
A YZ plane extending along the Y-axis and the Z-axis;
A crown transition point located at the most forward point of the crown within the YZ plane;
A rearward transition point located at the rearmost point of the crown within the YZ plane;
A crown axis extending between the crown transition point and the rear transition point;
Crown angle measured as the acute angle between the crown axis and the Y'-axis
A golf club head further comprising a crown angle greater than 75 degrees. A golf club head in claim 10, wherein the crown angle is greater than 85 degrees. In the first paragraph, a weight member is further included that is attached to the body in proximity to the rear end and the sole;
The above weight member determines the center of gravity of the weight member;
The weight member comprises a weight member height, the weight member height being determined by the distance between the center of gravity of the weight member and the center of gravity of the club head, measured parallel to the Y'-axis;
The weight member further comprises a weight member depth, the weight member depth being determined by the distance between the center of gravity of the weight member and the center of gravity of the club head, measured parallel to the Y'-axis;
The above club head has an E _W /D _W ratio defined as the weight member height divided by the weight member depth;
A golf club head having an E _W /D _W ratio greater than 0.3. As a golf club head:
A striking face including a geometric center and a leading edge, a body, a center of gravity, a ground plane and total club head mass; - said body including a crown, sole, heel, toe and rear end -;
A basic coordinate system centered around the geometric center, - said basic coordinate system being:
X-axis extending in the heel-toe direction parallel to the above ground plane;
A Y-axis extending in the crown-sole direction orthogonal to the above X-axis and the above ground plane;
- A Z-axis is defined extending in the direction of the striking surface-rear surface so as to be orthogonal to both the X-axis and the Y-axis;
An auxiliary coordinate system centered on the above center of gravity, - said auxiliary coordinate system being:
X'-axis extending in the heel-toe direction parallel to the above ground plane;
A Y'-axis extending in the crown-sole direction so as to be orthogonal to the above X'-axis and the above ground plane;
- A Z'-axis is defined that extends in the direction of the striking surface-rear surface so as to be orthogonal to both the X'-axis and the Y'-axis;
Including,
The above body:
Body width measured parallel to the X-axis between the heel and the toe;
Body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body;
having a body height measured parallel to the Y-axis between the ground plane and the highest point of the crown;
The above club head,
The H _B /W _B ratio defined as the body height divided by the body width, wherein the H _B /W _B ratio is greater than 0.6;
Moment of inertia about the X'-axis (Ixx);
Moment of inertia about the Y'-axis (Iyy);
Moment of inertia about the Z'-axis (Izz);
Ixx/Iyy ratio greater than 0.8;
A center mass region defined by an imaginary cylinder centered about the Y'-axis, said center mass region forming a center mass region radius of 0.75 inches;
The above club head has a mass distribution index (MD ₁ ) determined according to Equation 1:
(1)
- M _CMZ is the amount of mass within the center mass area, M _T is the total club head mass, and R _CMZ is the center mass area radius -;
A golf club head having a mass distribution index (MD ₁ ) greater than 0.1. In the 13th paragraph, further comprising a crown mass pad positioned on the inner surface of the crown and a sole mass pad positioned on the inner surface of the sole;
A golf club head wherein the crown mass pad and the sole mass pad each intersect the Y'-axis. A golf club head in claim 14, wherein at least one of the crown mass pad and the sole mass pad is defined entirely within the center mass area. As a golf club head:
A striking face including a geometric center and leading edge, a body, a center of gravity, a ground plane and total club head mass, said body including a crown, sole, heel, toe and rear end;
A basic coordinate system centered around the geometric center, - said basic coordinate system being:
X-axis extending in the heel-toe direction parallel to the above ground plane;
A Y-axis extending in the crown-sole direction orthogonal to the above X-axis and the above ground plane;
- A Z-axis is defined extending in the direction of the striking surface-rear surface so as to be orthogonal to both the X-axis and the Y-axis;
An auxiliary coordinate system centered on the above center of gravity, - said auxiliary coordinate system being:
X'-axis extending in the heel-toe direction parallel to the above ground plane;
A Y'-axis extending in the crown-sole direction so as to be orthogonal to the above X'-axis and the above ground plane;
- A Z'-axis is defined that extends in the direction of the striking surface-rear surface so as to be orthogonal to both the X'-axis and the Y'-axis;
Including,
The above body:
Body width measured parallel to the X-axis between the heel and the toe;
Body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body;
having a body height measured parallel to the Y-axis between the ground plane and the highest point of the crown;
The above club head,
The H _B /W _B ratio defined as the body height divided by the body width, wherein the H _B /W _B ratio is greater than 0.6;
Moment of inertia about the X'-axis (Ixx);
Moment of inertia about the Y'-axis (Iyy);
Moment of inertia about the Z'-axis (Izz);
Ixx/Iyy ratio greater than 0.8;
A center mass region defined by an imaginary cylinder centered about the Y'-axis, said center mass region forming a center mass region radius of 0.75 inches;
The above club head has a mass distribution index (MD ₃ ) determined according to Equation 1:
(1)
- M _CMZ is the mass within the center mass area and M _T is the total club head mass -;
A golf club head having a mass distribution index (MD ₃ ) greater than 0.005. In the 16th paragraph, a crown mass pad positioned on the inner surface of the crown and a sole mass pad positioned on the inner surface of the sole are further included.
A golf club head wherein the crown mass pad and the sole mass pad each intersect the Y'-axis. A golf club head in claim 17, wherein at least one of the crown mass pad and the sole mass pad is defined entirely within the center mass area. A golf club head in claim 16, wherein Iyy is less than 3200 g*㎠. A golf club head in claim 16, wherein Iyy is less than 2800 g*㎠. In the 16th paragraph, the striking surface further includes a bulge curvature and a roll curvature, and the bulge curvature has a bulge radius satisfying relationship 1;

A golf club head, wherein CGy is the position of the center of gravity along the Y-axis, and CGz is the position of the center of gravity along the Z-axis. In claim 16, the club head comprises a plurality of interchangeable weight inserts;
Each of said plurality of interchangeable weight inserts is associated with a different club head configuration;
Each club head configuration is associated with a different total club head mass;
A golf club head where Iyy is constant between each club head configuration.

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